Secondary Structure Adopted by the Gly-Gly-X Repetitive Regions of Dragline Spider Silk

Directory of Open Access Journals (Sweden)

Geoffrey M. Gray

2016-12-01

Full Text Available Solid-state NMR and molecular dynamics (MD simulations are presented to help elucidate the molecular secondary structure of poly(Gly-Gly-X, which is one of the most common structural repetitive motifs found in orb-weaving dragline spider silk proteins. The combination of NMR and computational experiments provides insight into the molecular secondary structure of poly(Gly-Gly-X segments and provides further support that these regions are disordered and primarily non-β-sheet. Furthermore, the combination of NMR and MD simulations illustrate the possibility for several secondary structural elements in the poly(Gly-Gly-X regions of dragline silks, including β-turns, 310-helicies, and coil structures with a negligible population of α-helix observed.

X-ray heating and ionization of broad-emission-line regions in QSO's and active galaxies

International Nuclear Information System (INIS)

Weisheit, J.C.; Shields, G.A.; Tarter, C.B.

1980-07-01

Absorption of x-rays deep within the broad-line emitting clouds in QSO's and the nuclei of active galaxies creates extensive zones of warm (T approx. 10 4 K), partially ionized N/sub e//N approx. 0.1) gas. Because Lyman alpha photons are trapped in these regions, the x-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. The HI regions plus the HII regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated Lα/Hα line emission ratios between 1 and 2. Enhanced MgII line emission from the HI regions gives rise to integrated MgII/Hα ratios near 0.5. The OI line lambda 8446 is efficiently pumped by trapped Hα photons and in the x-ray heated zone an intensity ratio I (lambda 8446)/I(Hα) approx. < 0.1 is calculated. All of these computed ratios now are in agreement with observations

Spatially resolved X-ray spectra of coronal active regions

International Nuclear Information System (INIS)

Catura, R.C.; Acton, L.W.; Joki, E.G.; Rapley, C.G.; Culhane, J.L.

1975-01-01

X-ray spectra from a number of coronal active regions were obtained during ATM support rocket flights carried out by the Lockheed group on June 11 and December 19, 1973. Multi-grid collimators were used to provide fields of view of 40ins. diameter and 90ins. diameter for a number of scanning crystal spectrometers and a bent crystal spectrometer which employed a position sensitive proportional counter to register the diffracted spectrum. A solar image was produced on film and on a TV camera on board the rocket with the aid of a 1 A Hα filter. A small part of the X-ray collimator was used to generate a multiple spot diffraction pattern which was superimposed on the Hα image and the composite picture was transmitted to the ground. Pre-launch calibrations allowed the spot corresponding to the X-ray collimator axis to be identified and so the collimator pointing direction on the solar disc was controlled from the ground by means of commands sent to the rocket. (Auth.)

Regions of incompatibility in single-stranded DNA bacteriophages phi X174 and G4

NARCIS (Netherlands)

van der Avoort, H. G.; van der Ende, A.; van Arkel, G. A.; Weisbeek, P. J.

1984-01-01

The intracellular presence of a recombinant plasmid containing the intercistronic region between the genes H and A of bacteriophage phi X174 strongly inhibits the conversion of infecting single-stranded phi X DNA to parental replicative-form DNA. Also, transfection with single-stranded or

X-ray emitting hot plasma in solar active regions observed by the SphinX spectrometer

Science.gov (United States)

Miceli, M.; Reale, F.; Gburek, S.; Terzo, S.; Barbera, M.; Collura, A.; Sylwester, J.; Kowalinski, M.; Podgorski, P.; Gryciuk, M.

2012-08-01

Aims: The detection of very hot plasma in the quiescent corona is important for diagnosing heating mechanisms. The presence and the amount of such hot plasma is currently debated. The SphinX instrument on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of energies well above 1 keV and provides the opportunity to detect the hot plasma component. Methods: We analysed the X-ray spectra of the solar corona collected by the SphinX spectrometer in May 2009 (when two active regions were present). We modelled the spectrum extracted from the whole Sun over a time window of 17 days in the 1.34-7 keV energy band by adopting the latest release of the APED database. Results: The SphinX broadband spectrum cannot be modelled by a single isothermal component of optically thin plasma and two components are necessary. In particular, the high statistical significance of the count rates and the accurate calibration of the spectrometer allowed us to detect a very hot component at ~7 million K with an emission measure of ~2.7 × 1044 cm-3. The X-ray emission from the hot plasma dominates the solar X-ray spectrum above 4 keV. We checked that this hot component is invariably present in both the high and low emission regimes, i.e. even excluding resolvable microflares. We also present and discuss the possibility of a non-thermal origin (which would be compatible with a weak contribution from thick-target bremsstrahlung) for this hard emission component. Conclusions: Our results support the nanoflare scenario and might confirm that a minor flaring activity is ever-present in the quiescent corona, as also inferred for the coronae of other stars.

The NuSTAR Hard X-Ray Survey of the Norma Arm Region

Energy Technology Data Exchange (ETDEWEB)

Fornasini, Francesca M. [Astronomy Department, University of California, 601 Campbell Hall, Berkeley, CA 94720 (United States); Tomsick, John A.; Chiu, Jeng-Lun; Clavel, Maïca; Krivonos, Roman A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Hong, JaeSub [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Gotthelf, Eric V.; Hailey, Charles J.; Mori, Kaya [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bauer, Franz; Corral-Santana, Jesús [Instituto de Astrofísica and Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Rahoui, Farid [European Southern Observatory, K. Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bodaghee, Arash [Georgia College, 231 W. Hancock Street, Milledgeville, GA 31061 (United States); Alexander, David M. [Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham, DH1 3LE (United Kingdom); Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, Institut de Recherche en Astrophysique et Planétologie, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Christensen, Finn E., E-mail: f.fornasini@berkeley.edu [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); and others

2017-04-01

We present a catalog of hard X-ray sources in a square-degree region surveyed by the Nuclear Spectroscopic Telescope Array ( NuSTAR ) in the direction of the Norma spiral arm. This survey has a total exposure time of 1.7 Ms, and the typical and maximum exposure depths are 50 ks and 1 Ms, respectively. In the area of deepest coverage, sensitivity limits of 5 × 10{sup −14} and 4 × 10{sup −14} erg s{sup −1} cm{sup −2} in the 3–10 and 10–20 keV bands, respectively, are reached. Twenty-eight sources are firmly detected, and 10 are detected with low significance; 8 of the 38 sources are expected to be active galactic nuclei. The three brightest sources were previously identified as a low-mass X-ray binary, high-mass X-ray binary, and pulsar wind nebula. Based on their X-ray properties and multiwavelength counterparts, we identify the likely nature of the other sources as two colliding wind binaries, three pulsar wind nebulae, a black hole binary, and a plurality of cataclysmic variables (CVs). The CV candidates in the Norma region have plasma temperatures of ≈10–20 keV, consistent with the Galactic ridge X-ray emission spectrum but lower than the temperatures of CVs near the Galactic center. This temperature difference may indicate that the Norma region has a lower fraction of intermediate polars relative to other types of CVs compared to the Galactic center. The NuSTAR log N –log S distribution in the 10–20 keV band is consistent with the distribution measured by Chandra at 2–10 keV if the average source spectrum is assumed to be a thermal model with kT  ≈ 15 keV, as observed for the CV candidates.

Broadband X-ray Imaging in the Near-Field Region of an Airblast Atomizer

Science.gov (United States)

Li, Danyu; Bothell, Julie; Morgan, Timothy; Heindel, Theodore

2017-11-01

The atomization process has a close connection to the efficiency of many spray applications. Examples include improved fuel atomization increasing the combustion efficiency of aircraft engines, or controlled droplet size and spray angle enhancing the quality and speed of the painting process. Therefore, it is vital to understand the physics of the atomization process, but the near-field region is typically optically dense and difficult to probe with laser-based or intrusive measurement techniques. In this project, broadband X-ray radiography and X-ray computed tomography (CT) imaging were performed in the near-field region of a canonical coaxial airblast atomizer. The X-ray absorption rate was enhanced by adding 20% by weight of Potassium Iodide to the liquid phase to increase image contrast. The radiographs provided an estimate of the liquid effective mean path length and spray angle at the nozzle exit for different flow conditions. The reconstructed CT images provided a 3D map of the time-average liquid spray distribution. X-ray imaging was used to quantify the changes in the near-field spray characteristics for various coaxial airblast atomizer flow conditions. Office of Naval Research.

Performance of room temperature mercuric iodide (HgI2) detectors in the ultra low energy x-ray region

International Nuclear Information System (INIS)

Dabrowski, A.J.; Iwanczyk, J.S.; Barton, J.B.; Huth, G.C.; Whited, R.; Ortale, C.; Economou, T.E.; Turkevich, A.L.

1980-01-01

Performance of room temperature mercuric iodide x-ray spectrometers has been recently improved through new fabrication techniques and further development of low noise associated electronic systems. This progress has extended the range of measurements to the ultra low energy x-ray region at room temperature. This paper reports the study of the effect of contact material on the performance of HgI 2 detectors in the low energy x-ray region

A BMP responsive transcriptional region in the chicken type X collagen gene.

Science.gov (United States)

Volk, S W; Luvalle, P; Leask, T; Leboy, P S

1998-10-01

Bone morphogenetic proteins (BMPs) were originally identified by their ability to induce ectopic bone formation and have been shown to promote both chondrogenesis and chondrocyte hypertrophy. BMPs have recently been found to activate a membrane serine/threonine kinase signaling mechanism in a variety of cell types, but the downstream effectors of BMP signaling in chondrocyte differentiation remain unidentified. We have previously reported that BMP-2 markedly stimulates type X collagen expression in prehypertrophic chick sternal chondrocytes, and that type X collagen mRNA levels in chondrocytes cultured under serum-free (SF) conditions are elevated 3- to 5-fold within 24 h. To better define the molecular mechanisms of induction of chondrocyte hypertrophy by BMPs, we examined the effect of BMPs on type X collagen production by 15-day chick embryo sternal chondrocytes cultured under SF conditions in the presence or absence of 30 ng/ml BMP-2, BMP-4, or BMP-7. Two populations of chondrocytes were used: one representing resting cartilage isolated from the caudal third of the sterna and the second representing prehypertrophic cartilage from the cephalic third of the sterna. BMP-2, BMP-4, and BMP-7 all effectively promoted chondrocyte maturation of cephalic sternal chondrocytes as measured by high levels of alkaline phosphatase, diminished levels of type II collagen, and induction of the hypertrophic chondrocyte-specific marker, type X collagen. To test whether BMP control of type X collagen expression occurs at the transcriptional level, we utilized plasmid constructs containing the chicken collagen X promoter and 5' flanking regions fused to a reporter gene. Constructs were transiently transfected into sternal chondrocytes cultured under SF conditions in the presence or absence of 30 ng/ml BMP-2, BMP-4, or BMP-7. A 533 bp region located 2.4-2.9 kb upstream from the type X collagen transcriptional start site was both necessary and sufficient for strong BMP responsiveness

The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR

DEFF Research Database (Denmark)

Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.

2016-01-01

We present the first observations of quiescent active regions (ARs) using the Nuclear Spectroscopic Telescope Array (NuSTAR), a focusing hard X-ray telescope capable of studying faint solar emission from high-temperature and non-thermal sources. We analyze the first directly imaged and spectrally...... resolved X-rays above 2 keV from non-flaring ARs, observed near the west limb on 2014 November 1. The NuSTAR X-ray images match bright features seen in extreme ultraviolet and soft X-rays. The NuSTAR imaging spectroscopy is consistent with isothermal emission of temperatures 3.1-4.4 MK and emission...

X-ray Binaries in the Central Region of M31

Science.gov (United States)

Trudolyubov, Sergey P.; Priedhorsky, W. C.; Cordova, F. A.

2006-09-01

We present the results of the systematic survey of X-ray sources in the central region of M31 using the data of XMM-Newton observations. The spectral properties and variability of 124 bright X-ray sources were studied in detail. We found that more than 80% of sources observed in two or more observations show significant variability on the time scales of days to years. At least 50% of the sources in our sample are spectrally variable. The fraction of variable sources in our survey is much higher than previously reported from Chandra survey of M31, and is remarkably close to the fraction of variable sources found in M31 globular cluster X-ray source population. We present spectral distribution of M31 X-ray sources, based on the spectral fitting with a power law model. The distribution of spectral photon index has two main peaks at 1.8 and 2.3, and shows clear evolution with source luminosity. Based on the similarity of the properties of M31 X-ray sources and their Galactic counterparts, we expect most of X-ray sources in our sample to be accreting binary systems with neutron star and black hole primaries. Combining the results of X-ray analysis (X-ray spectra, hardness-luminosity diagrams and variability) with available data at other wavelengths, we explore the possibility of distinguishing between bright neutron star and black hole binary systems, and identify 7% and 25% of sources in our sample as a probable black hole and neutron star candidates. Finally, we compare the M31 X-ray source population to the source populations of normal galaxies of different morphological type. Support for this work was provided through NASA Grant NAG5-12390. Part of this work was done during a summer workshop ``Revealing Black Holes'' at the Aspen Center for Physics, S. T. is grateful to the Center for their hospitality.

The Northern regional programme for the acceptance testing of X-ray equipment

International Nuclear Information System (INIS)

Faulkner, K.; Harrison, R.M.; Kotre, C.J.; Smith, S.; Davies, M.; Barker, P.

1989-01-01

Since 1984 the UK Northern Regional Medical Physics Department has participated in a regional acceptance testing programme for all X-ray equipment from mobile units to computed tomography scanners. Organizational and radiation physics aspects of the programme are described. Three levels of tests are performed by physicists: the first on installation, the second after 3 months, the final visit just prior to the end of the manufacturers warranty. The second test is only performed if any aspect of performance requires rechecking as a result of the first. Acceptance test protocols are based on those published by the Institute of Physical Sciences in Medicine. Details limiting values for the acceptance test measurements are given. In some instances testing has resulted in modifications to the design and construction of X-ray equipment. Acceptance testing is important in determining a baseline standard of performance against which routine quality assurance may be assessed. (author)

Observation of parametric X-ray radiation in an anomalous diffraction region

Energy Technology Data Exchange (ETDEWEB)

Alexeyev, V.I., E-mail: vial@x4u.lebedev.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Eliseyev, A.N., E-mail: elisseev@pluton.lpi.troitsk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Irribarra, E., E-mail: esteban.irribarra@epn.edu.ec [Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito (Ecuador); Kishin, I.A., E-mail: ivan.kishin@mail.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Kubankin, A.S., E-mail: kubankin@bsu.edu.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Nazhmudinov, R.M., E-mail: fizeg@bk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation)

2016-08-19

A new possibility to expand the energy region of diffraction processes based on the interaction of relativistic charged particles with crystalline structures is presented. Diffracted photons related to parametric X-ray radiation produced by relativistic electrons are detected below the low energy threshold for the X-ray diffraction mechanism in crystalline structures for the first time. The measurements were performed during the interaction of 7 MeV electrons with a textured polycrystalline tungsten foil and a highly oriented pyrolytic graphite crystal. The experiment results are in good agreement with a developed model based on the PXR kinematical theory. The developed experimental approach can be applied to separate the contributions of real and virtual photons to the total diffracted radiation generated during the interaction of relativistic charged particles with crystalline targets. - Highlights: • Parametric X-ray radiation below the low energy threshold for diffraction of free X-rays. • Experimental separation of the contributions from different radiation mechanisms. • PXR from relativistic electrons in mosaic crystals and textured polycrystlas.

X-RAY AND RADIO OBSERVATIONS OF THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

Energy Technology Data Exchange (ETDEWEB)

Montes, V. A.; Hofner, P.; Anderson, C.; Rosero, V. [Physics Department, New Mexico Tech, 801 Leroy Place, Socorro, NM 87801 (United States)

2015-08-15

We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6 cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17′ × 17′ ACIS-I field, and a total of 13 radio sources within the 9.′2 primary beam at 4.9 GHz. Among these observtions are the first 6 cm detections of the central sources reported by Hofner et al., namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6 cm counterparts. Based on an NIR color–color analysis and on the Besançon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from the massive protostar.

THE CONFINED X-CLASS FLARES OF SOLAR ACTIVE REGION 2192

Energy Technology Data Exchange (ETDEWEB)

Thalmann, J. K.; Su, Y.; Temmer, M.; Veronig, A. M., E-mail: julia.thalmann@uni-graz.at [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5/II, 8010 Graz (Austria)

2015-03-10

The unusually large active region (AR) NOAA 2192, observed in 2014 October, was outstanding in its productivity of major two-ribbon flares without coronal mass ejections. On a large scale, a predominantly north–south oriented magnetic system of arcade fields served as a strong top and lateral confinement for a series of large two-ribbon flares originating from the core of the AR. The large initial separation of the flare ribbons, together with an almost absent growth in ribbon separation, suggests a confined reconnection site high up in the corona. Based on a detailed analysis of the confined X1.6 flare on October 22, we show how exceptional the flaring of this AR was. We provide evidence for repeated energy release, indicating that the same magnetic field structures were repeatedly involved in magnetic reconnection. We find that a large number of electrons was accelerated to non-thermal energies, revealing a steep power-law spectrum, but that only a small fraction was accelerated to high energies. The total non-thermal energy in electrons derived (on the order of 10{sup 25} J) is considerably higher than that in eruptive flares of class X1, and corresponds to about 10% of the excess magnetic energy present in the active-region corona.

Measurements of additional X-ray flux in South Atlantic magnetic anomaly region

International Nuclear Information System (INIS)

Martin, I.M.

1968-01-01

The purpose of this study is the calculation of the additional X-ray flux (20 - 150 KeV), produced by electron precipitation in the South Atlantic anomaly region. The kind of detector and the technique employed in the observations of this flux, utilizing stratospheric balloons as a means of transport of the payload across the anomaly region, are described. The results of two balloon launchins in Sao Jose dos Campos in July 1968, with the expected flux, are compared. (author) [pt

A study of x-ray emission from the anode region in a plasma focus device

International Nuclear Information System (INIS)

Jia Wang; Tsinchi Yang

1988-01-01

The physical process of x-ray emission from the anode region in a plasma focus device due to the interaction of a powerful electron beam with the metal anode and with ionised metallic vapour from the anode is investigated. The influence of the magnetic field of the beam is taken into consideration. A MC-PIC model (Monte Carlo-particle in cell) is proposed for the process, in which an electron-photon collision cascade is simulated by the MC approach and the time-dependent state of metallic vapour is determined by PIC computation. The time-resolved energy spectra and angular distributions of x-ray emission from the extending anode region are calculated. The time-integrated characteristics of the x-ray emission can be compared with the results of experiments as far as they are available. (author)

The Northern Regional Programme for the acceptance testing of X-ray equipment

International Nuclear Information System (INIS)

Faulkner, K.; Harrison, R.M.; Kotre, C.J.; Smith, S.; Davies, M.; Barker, P.

1989-01-01

Since 1984 the Regional Medical Physics Department has participated in a regional acceptance testing programme for all X-ray equipment from mobile units to computed tomography scanners. The organizational and radiation physics aspects of the programme are described. Three levels of tests are performed by physicists: the first on installation, the second after 3 months, and the final visit just prior to the end of the manufacturer's warranty. The second test is only performed if any aspect of performance requires rechecking as a result of the first visit. Acceptance test protocols are based on those published by the Institute of Physical Sciences in Medicine. Details of the limiting values for the acceptance test measurements are given. The results of the programme are discussed. In some instances the testing has resulted in modifications to the design and construction of X-ray equipment. Acceptance testing is important in determining a baseline standard of performance against which routine quality assurance may be assessed. (author)

A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

International Nuclear Information System (INIS)

Burion, Steve; Funk, Tobias; Speidel, Michael A.

2013-01-01

Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm 2 , calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 ± 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without compromising

Sequence analysis of the breakpoint regions of an X;5 translocation in a female with Duchenne muscular dystrophy

Energy Technology Data Exchange (ETDEWEB)

Bakel, I. van; Holt, S.; Craig, I. [Univ. of Oxford (United Kingdom)] [and others

1995-08-01

X;autosome translocations in females with Duchenne muscular dystrophy (DMD) provide an opportunity to study the mechanisms responsible for chromosomal rearrangements that occur in the germ line. We describe here a detailed molecular analysis of the translocation breakpoints of an X;autosome reciprocal translocation, t(X;5) (p21;q31.1), in a female with DMD. Cosmid clones that contained the X-chromosome breakpoint region were identified, and subclones that hybridized to the translocation junction fragment in restriction digests of the patient`s DNA were isolated and sequenced. Primers designed from the X-chromosomal sequence were used to obtain the junction fragments on the der(X) and the der(5) by inverse PCR. The resultant clones were also cloned and sequenced, and this information used to isolate the chromosome 5 breakpoint region. Comparison of the DNA sequences of the junction fragments with those of the breakpoint regions on chromosomes X and 5 revealed that the translocation arose by nonhomologous recombination with an imprecise reciprocal exchange. Four and six base pairs of unknown origin are inserted at the exchange points of the der(X) and der(5), respectively, and three nucleotides are deleted from the X-chromosome sequence. Two features were found that may have played a role in the generation of the translocation. These were (1) a repeat motif with an internal homopyrimidine stretch 10 bp upstream from the X-chromosome breakpoint and (2) a 9-bp sequence of 78% homology located near the breakpoints on chromosomes 5 and X. 32 refs., 4 figs., 2 tabs.

Microwave, EUV, and X-ray observations of active region loops and filaments

International Nuclear Information System (INIS)

Schmahl, E.

1980-01-01

Until the advent of X-ray and EUV observations of coronal structures, radio observers were forced to rely on eclipse and coronagraph observations in white light and forbidden coronal lines for additional diagnostics of the high temperature microwave sources. While these data provided enough material for theoretical insight into the physics of active regions, there was no way to make direct, simultaneous comparison of coronal structures on the disk as seen at microwave and optical wavelengths. This is now possible, and therefore the author summarizes the EUV and X-ray observations indicating at each point the relevance to microwaves. (Auth.)

Magneto-static Modeling from Sunrise/IMaX: Application to an Active Region Observed with Sunrise II

Energy Technology Data Exchange (ETDEWEB)

Wiegelmann, T.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; Noort, M. van [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Neukirch, T. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom); Nickeler, D. H. [Astronomical Institute, AV CR, Fricova 298, 25165 Ondrejov (Czech Republic); Rodríguez, J. Blanco [Grupo de Astronomía y Ciencias del Espacio, Universidad de Valencia, E-46980 Paterna, Valencia (Spain); Iniesta, J. C. Del Toro; Suárez, D. Orozco [Instituto de Astrofísica de Andalucía (CSIC), Apartado de Correos 3004, E-18080 Granada (Spain); Schmidt, W. [Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, D-79104 Freiburg (Germany); Pillet, V. Martínez [National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303 (United States); Knölker, M., E-mail: wiegelmann@mps.mpg.de [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

2017-03-01

Magneto-static models may overcome some of the issues facing force-free magnetic field extrapolations. So far they have seen limited use and have faced problems when applied to quiet-Sun data. Here we present a first application to an active region. We use solar vector magnetic field measurements gathered by the IMaX polarimeter during the flight of the Sunrise balloon-borne solar observatory in 2013 June as boundary conditions for a magneto-static model of the higher solar atmosphere above an active region. The IMaX data are embedded in active region vector magnetograms observed with SDO /HMI. This work continues our magneto-static extrapolation approach, which was applied earlier to a quiet-Sun region observed with Sunrise I. In an active region the signal-to-noise-ratio in the measured Stokes parameters is considerably higher than in the quiet-Sun and consequently the IMaX measurements of the horizontal photospheric magnetic field allow us to specify the free parameters of the model in a special class of linear magneto-static equilibria. The high spatial resolution of IMaX (110–130 km, pixel size 40 km) enables us to model the non-force-free layer between the photosphere and the mid-chromosphere vertically by about 50 grid points. In our approach we can incorporate some aspects of the mixed beta layer of photosphere and chromosphere, e.g., taking a finite Lorentz force into account, which was not possible with lower-resolution photospheric measurements in the past. The linear model does not, however, permit us to model intrinsic nonlinear structures like strongly localized electric currents.

GIANT H II REGIONS IN M101. I. X-RAY ANALYSIS OF HOT GAS

International Nuclear Information System (INIS)

Sun Wei; Chen Yang; Feng Li; Chu, You-Hua; Chen, C.-H. Rosie; Wang, Q. Daniel; Li Jiangtao

2012-01-01

We performed a Chandra X-ray study of three giant H II regions (GHRs), NGC 5461, NGC 5462, and NGC 5471, in the spiral galaxy M101. The X-ray spectra of the three GHRs all contain a prominent thermal component with a temperature of ∼0.2 keV. In NGC 5461, the spatial distribution of the soft ( 52 erg, is consistent with a hypernova origin. In addition, a bright source in the field of NGC 5462 has been identified as a background active galactic nucleus, instead of a black hole X-ray binary in M101.

Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

Science.gov (United States)

Bruner, M.; Brown, W. A.; Haisch, B. M.

1987-01-01

A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique.

Photoacoustical and pyroelectric dosimetry of X-ray radiation in diagnostic region

International Nuclear Information System (INIS)

Carvalho, A.A. de.

1987-01-01

Three new types of radiation dosimeters, designed to measure X rays in its diagnostic region are described: the pulsed photoacoustical radiation dosimeter, the pyroelectric radiation dosimeter and the pulsed pyroelectric radiation dosimeter. The photoacoustical radiation dosimeter with the scope of to compare its carachteristics with the carachteristics of the new developed dosimeters is also studied. A methodology for calibration of a photoacoustical dosimeter which doesn't require the calibration of its response in a known field of ionizing radiation is proposed. A theoretical model to explain the results produced by the pulsed pyroelectric radiation dosimeter is presented. The obtained results show that the developed dosimeters are of calorimetric type, being linear its response with the X ray energy fluence rate. (author) [pt

A fluorescence XAFS measurement instrument in the soft x-ray region toward observation under operando conditions

Energy Technology Data Exchange (ETDEWEB)

Honda, M., E-mail: honda.mitsunori@jaea.go.jp; Baba, Y.; Shimoyama, I.; Sekiguchi, T. [Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2015-03-15

X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO{sub 4}{sup 2−} when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.

X-ray-induced specific-locus mutations in the ad-3 region of two-component heterokaryons of Neurospora crassa

International Nuclear Information System (INIS)

Serres, F.J. de

1989-01-01

More extensive genetic tests have been preformed on a series of 832 X-ray-induced specific-locus mutations in the ad-3 region of a 2-component heterokaryon of Neurospora crassa, reported earlier. Using new tester strains and techniques for performing large-scale genetic tests to characterize ad-3 mutants induced in 2-component heterokaryons, new data have been obtained on this sample of X-ray-induced mutants. These new data show that unexpectedly high frequencies of both single-locus mutations and multilocus deletions in the ad-3 region have addition, but separate, sites of recessive lethal damage in the imeediately adjacent genetic regions. The frequencies of these X-ray-induced multiple-locus mutants in the ad-3 region are orders of magnitude higher than expected on the basis of target theory and classical models of chromosome structure during interphase. Current models of interphase chromosome structure in higher eukaryotes as revealed by chromosome 'painting' offer a possible explanation of the Neurospora data. (author). 25 refs.; 5 figs

The LHC can probe small x PDFs; the treatment of the infrared region

Energy Technology Data Exchange (ETDEWEB)

Martin, A. D.; De Oliveira, E. G.; Ryskin, M. G. [Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE (United Kingdom)

2013-04-15

First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements of parton distribution functions in the low x domain; x Less-Than-Or-Equivalent-To 10{sup -4}. Second, we find an inconsistency in the conventional NLO treatment of the infrared region. We illustrate the problem using the NLO coefficient function of Drell-Yan production.

The complete Einstein Observatory X-ray survey of the Orion Nebula region.

Science.gov (United States)

Gagne, Marc; Caillault, Jean-Pierre

1994-01-01

We have analyzed archival Einstein Observatory images of a roughly 4.5 square degree region centered on the Orion Nebula. In all, 245 distinct X-ray sources have been detected in six High Resolution Imager (HRI) and 17 Imaging Proportional Counter (IPC) observations. An optical database of over 2700 stars has been assembled to search for candidate counterparts to the X-ray sources. Roughly half the X-ray sources are identified with a single Orion Nebula cluster member. The 10 main-sequence O6-B5 cluster stars detected in Orion have X-ray activity levels comparable to field O and B stars. X-ray emission has also been detected in the direction of four main-sequence late-B and early-A type stars. Since the mechanisms producing X-rays in late-type coronae and early-type winds cannot operate in the late-B and early-A type atmospheres, we argue that the observed X-rays, with L(sub X) approximately = 3 x 10(exp 30) ergs/s, are probably produced in the coronae of unseen late-type binary companions. Over 100 X-ray sources have been associated with late-type pre-main sequence stars. The upper envelope of X-ray activity rises sharply from mid-F to late-G, with L(sub x)/L(sub bol) in the range 10(exp -4) to 2 x 10(exp -3) for stars later than approximately G7. We have looked for variability of the late-type cluster members on timescales of a day to a year and find that 1/4 of the stars show significantly variable X-ray emission. A handful of the late-type stars have published rotational periods and spectroscopic rotational velocities; however, we see no correlation between X-ray activity and rotation. Thus, for this sample of pre-main-sequence stars, the large dispersion in X-ray activity does not appear to be caused by the dispersion in rotation, in contrast with results obtained for low-mass main-sequence stars in the Pleiades and pre-main-sequence stars in Taurus-Auriga.

Investigations of some regional river systems by INAA and X-ray fluorescence

International Nuclear Information System (INIS)

Drazhkovich, R.J.; Kukoch, A.

1985-01-01

Distribution of Zn, Hg, Sb, Cr, Fe, Sc and Co has been investigated in materials dissolved and suspended in the rivers Ibar, Zapadna Morava and Kamenica by means of INAA and X-ray fluorescence. Irradiation was made in VKG-channels of RA-nuclear reactor Vincha. Distribution coefficients were calculated, as well as contamination factors for investigated river regional systems in comparison to the uncontaminated water system. Data obtained indicate the possibility of utilization of these two analytical methods for investigation and control of biogeochemical and contamination processes in small regional water systems, especially important for modern studies in life sciences

X-linked recessive panhypopituitarism associated with a regional duplication in Xq25-q26.

Science.gov (United States)

Lagerström-Fermér, M; Sundvall, M; Johnsen, E; Warne, G L; Forrest, S M; Zajac, J D; Rickards, A; Ravine, D; Landegren, U; Pettersson, U

1997-01-01

We present a linkage analysis and a clinical update on a previously reported family with X-linked recessive panhypopituitarism, now in its fourth generation. Affected members exhibit variable degrees of hypopituitarism and mental retardation. The markers DXS737 and DXS1187 in the q25-q26 region of the X chromosome showed evidence for linkage with a peak LOD score (Zmax) of 4.12 at zero recombination fraction (theta(max) = 0). An apparent extra copy of the marker DXS102, observed in the region of the disease gene in affected males and heterozygous carrier females, suggests that a segment including this marker is duplicated. The gene causing this disorder appears to code for a dosage-sensitive protein central to development of the pituitary. Images Figure 2 PMID:9106538

The Highest Resolution X-ray View of the Nuclear Region of NGC 4151

Science.gov (United States)

Wang, Junfeng; Fabbiano, G.; Karovska, M.; Elvis, M.; Risaliti, G.; Zezas, A.; Mundell, C. G.

2009-09-01

We report high resolution imaging of the nucleus of the Seyfert 1 galaxy NGC 4151 obtained with a 50 ks Chandra HRC observation. The HRC image resolves the emission on spatial scales of 0.5 arcsec (30 pc), showing an extended X-ray morphology overall consistent with the narrow line region seen in optical line emission. Removal of the bright point-like nuclear source and image deconvolution technique both reveal X-ray enhancements that closely match the substructures seen in the HST [OIII] image and prominent knots in the radio jet. We find that most of the NLR clouds in NGC 4151 have [OIII] to soft X-ray ratio consistent with the values observed in NLRs of some Seyfert 2 galaxies, which indicates a uniform ionization parameter even at large radii and a density dependence ∝ r^{-2} as expected in the disk wind scenario. We examine various X-ray emission mechanisms of the radio jet and consider thermal emission from interaction between radio outflow and the NLR clouds the most probable origin for the X-ray emission associated with the jet.

X-ray sources in regions of star formation. I. The naked T Tauri stars

International Nuclear Information System (INIS)

Walter, F.M.

1986-01-01

Einstein X-ray observations of regions of active star formation in Taurus, Ophiuchus, and Corona Australis show a greatly enhanced surface density of stellar X-ray sources over that seen in other parts of the sky. Many of the X-ray sources are identified with low-mass, pre-main-sequence stars which are not classical T Tauri stars. The X-ray, photometric, and spectroscopic data for these stars are discussed. Seven early K stars in Oph and CrA are likely to be 1-solar-mass post-T Tauri stars with ages of 10-million yr. The late K stars in Taurus are not post-T Tauri, but naked T Tauri stars, which are coeval with the T Tauri stars, differing mainly in the lack of a circumstellar envelope. 72 references

Fine genetic structure of the 2D3-2F5 region of the X-chromosome of Drosophila melanogaster

International Nuclear Information System (INIS)

Gvozdev, V.A.; Gostimsky, S.A.; Gerasimova, T.I.; Dubrovskaya, E.S.; Braslavskaya, O.Yu.

1975-01-01

97 lethal and semilethal mutations were induced by ethyl methanesulfonate, nitrosomethyl urea and γ-irradiation in the 2D3-F5 region of the X-chromosome of D. melanogaster. Approximately 1 per cent of the tested X-chromosomes carried a lethal in the 2D3-2F5 region. The mutation frequencies per band of DNA content in this region and the whole X-chromosome are equal. Complementation analysis revealed at least 10 functionally independent essential loci in this region including about 10 bands. The data presented in this study support the one band - one gene hypothesis. The Pgd locus coding for 6-phosphogluconate dehydrogenase (6PGD) is mapped in the 2D3 (or 2D4) band. Isolation of 11 lethal or semilethal point mutations with null or reduced 6PGD acticity shows that the Pgd locus is a vital one. (orig.) [de

An Extension of the Miller Equilibrium Model into the X-Point Region

Science.gov (United States)

Hill, M. D.; King, R. W.; Stacey, W. M.

2017-10-01

The Miller equilibrium model has been extended to better model the flux surfaces in the outer region of the plasma and scrape-off layer, including the poloidally non-uniform flux surface expansion that occurs in the X-point region(s) of diverted tokamaks. Equations for elongation and triangularity are modified to include a poloidally varying component and grad-r, which is used in the calculation of the poloidal magnetic field, is rederived. Initial results suggest that strong quantitative agreement with experimental flux surface reconstructions and strong qualitative agreement with poloidal magnetic fields can be obtained using this model. Applications are discussed. A major new application is the automatic generation of the computation mesh in the plasma edge, scrape-off layer, plenum and divertor regions for use in the GTNEUT neutral particle transport code, enabling this powerful analysis code to be routinely run in experimental analyses. Work supported by US DOE under DE-FC02-04ER54698.

Charmonium resonances in the 3.9 GeV/c2 energy region and the X(3915)/X(3930) puzzle

Science.gov (United States)

Ortega, Pablo G.; Segovia, Jorge; Entem, David R.; Fernández, Francisco

2018-03-01

An interesting controversy has emerged challenging the widely accepted nature of the X (3915) and the X (3930) resonances, which had initially been assigned to the χc0 (2 P) and χc2 (2 P) c c bar states, respectively. To unveil their inner structure, the properties of the JPC =0++ and JPC =2++ charmonium states in the energy region of these resonances are analyzed in the framework of a constituent quark model. Together with the bare q q bar states, threshold effects due to the opening of nearby meson-meson channels are included in a coupled-channels scheme calculation. We find that the structure of both states is dominantly molecular with a probability of bare q q bar states lower than 45%. Our results favor the hypothesis that X (3915) and X (3930) resonances arise as different decay mechanisms of the same JPC =2++ state. Moreover we find an explanation for the recently discovered M = 3860MeV /c2 as a JPC =0++ 2P state and rediscover the lost Y (3940) as an additional state in the JPC =0++ family.

MAGNETIC NON-POTENTIALITY OF SOLAR ACTIVE REGIONS AND PEAK X-RAY FLUX OF THE ASSOCIATED FLARES

International Nuclear Information System (INIS)

Tiwari, Sanjiv Kumar; Venkatakrishnan, P.; Gosain, Sanjay

2010-01-01

Predicting the severity of solar eruptive phenomena such as flares and coronal mass ejections remains a great challenge despite concerted efforts to do so over the past several decades. However, the advent of high-quality vector magnetograms obtained from Hinode (SOT/SP) has increased the possibility of meeting this challenge. In particular, the spatially averaged signed shear angle (SASSA) seems to be a unique parameter for quantifying the non-potentiality of active regions. We demonstrate the usefulness of the SASSA for predicting flare severity. For this purpose, we present case studies of the evolution of magnetic non-potentiality using 115 vector magnetograms of four active regions, namely, ARs NOAA 10930, 10960, 10961, and 10963 during 2006 December 8-15, 2007 June 3-10, 2007 June 28-July 5, and 2007 July 10-17, respectively. The NOAA ARs 10930 and 10960 were very active and produced X and M class flares, respectively, along with many smaller X-ray flares. On the other hand, the NOAA ARs 10961 and 10963 were relatively less active and produced only very small (mostly A- and B-class) flares. For this study, we have used a large number of high-resolution vector magnetograms obtained from Hinode (SOT/SP). Our analysis shows that the peak X-ray flux of the most intense solar flare emanating from the active regions depends on the magnitude of the SASSA at the time of the flare. This finding of the existence of a lower limit of the SASSA for a given class of X-ray flares will be very useful for space weather forecasting. We have also studied another non-potentiality parameter called the mean weighted shear angle (MWSA) of the vector magnetograms along with the SASSA. We find that the MWSA does not show such distinction as the SASSA for upper limits of the GOES X-ray flux of solar flares; however, both the quantities show similar trends during the evolution of all active regions studied.

The Relation Between Magnetic Fields and X-ray Emission for Solar Microflares and Active Regions

Science.gov (United States)

Kirichenko, A. S.; Bogachev, S. A.

2017-09-01

We present the result of a comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we used the monochromatic MgXII Imaging Spectroheliometer (MISH), the Full-disk EUV Telescope (FET), and the Solar PHotometer in X-rays (SphinX) instruments onboard the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon CORONAS- Photon spacecraft because of their high sensitivity in soft X-rays. The peak flare flux (PFF) for solar microflares was found to depend on the strength of the magnetic field and on the total unsigned magnetic flux as a power-law function. In the spectral range 2.8 - 36.6 Å, which shows very little increase related to microflares, the power-law index of the relation between the X-ray flux and magnetic flux for active regions is 1.48 ±0.86, which is close to the value obtained previously by Pevtsov et al. ( Astrophys. J. 598, 1387, 2003) for different types of solar and stellar objects. In the spectral range 1 - 8 Å, the power-law indices for PFF(B) and PFF(Φ) for microflares are 3.87 ±2.16 and 3 ±1.6, respectively. We also make suggestions on the heating mechanisms in active regions and microflares under the assumption of loops with constant pressure and heating using the Rosner-Tucker-Vaiana scaling laws.

Background estimation in short-wave region during determination of total sample composition by x-ray fluorescence method

International Nuclear Information System (INIS)

Simakov, V.A.; Kordyukov, S.V.; Petrov, E.N.

1988-01-01

Method of background estimation in short-wave spectral region during determination of total sample composition by X-ray fluorescence method is described. 13 types of different rocks with considerable variations of base composition and Zr, Nb, Th, U content below 7x10 -3 % are investigated. The suggested method of background accounting provides for a less statistical error of the background estimation than direct isolated measurement and reliability of its determination in a short-wave region independent on the sample base. Possibilities of suggested method for artificial mixtures conforming by the content of main component to technological concemtrates - niobium, zirconium, tantalum are estimated

Testing the tetraquark structure for the X resonances in the low-lying region

Energy Technology Data Exchange (ETDEWEB)

Kim, Hungchong [Kookmin University, Department of General Education, Seoul (Korea, Republic of); Kim, K.S. [Korea Aerospace University, School of Liberal Arts and Science, Goyang (Korea, Republic of); Cheoun, Myung-Ki [Soongsil University, Department of Physics, Seoul (Korea, Republic of); Jido, Daisuke [Tokyo Metropolitan University, Department of Physics, Hachioji, Tokyo (Japan); Oka, Makoto [Tokyo Institute of Technology, Department of Physics, Meguro (Japan); Japan Atomic Energy Agency, Advanced Science Research Center, Tokai, Ibaraki (Japan)

2016-07-15

Assuming the four-quark structure for the X resonances in the low-lying region, we calculate their masses using the color-spin interaction. Specifically, the hyperfine masses of the color-spin interaction are calculated for the possible states in spin-0, spin-1, spin-2 channels. The two states in spin-0 channel as well as the two states in spin-1 channel are diagonalized in order to generate the physical hyperfine masses. By matching the difference in hyperfine masses with the splitting in corresponding hadron masses and using the X(3872) mass as an input, we estimate the masses corresponding to the states J{sup PC} = 0{sup ++}, 1{sup +-}, 2{sup ++}. We find that the masses of two states in 1{sup +-} are close to those of X(3823), X(3900), and the mass of the 2{sup ++} state is close to that of X(3940). For them, the discrepancies are about ∝ 10 MeV. This may suggest that the quantum numbers of the controversial states are X(3823) = 1{sup +-}, X(3900) = 1{sup +-}, X(3940) = 2{sup ++}. In this work, we use the same inputs parameters, the constituent quark masses and the strength of the color-spin interaction, that have been adopted in the previous work on the D- or B-meson excited states. There, it was shown that the four-quark structure can be manifested in their excited states. Thus, our results in this work provide a consistent treatment on open- and hidden-charm mesons as far as the four-quark model is concerned. (orig.)

Electric resistivity of Y (Fe1-xAlx)2 compounds in the spin glass region (0,10<x<0,35)

International Nuclear Information System (INIS)

Souza, G.P. de.

1985-01-01

Measurements of electric resistivity in function of the temperature (1.5 1-x Al x2 pseudobinary intermetallic compounds in the region of concentration where there is a spin-glass behaviour, were carried out. The obtained results distinguished two behaviours. In certain cocentration, the minimum of resistivity at low temperatures was observed and in the others, a decrease of resistivity with increase of temperature up to environment temperature was found out. Magnetometry measurements, were carried out aiming to determine freezing critical temperature and of the order of long range, making possible to obtain more accurate measurements in the temperature range where the spin-glass, ferromagnetic and paramagnetic states occur in the compounds. (M.C.K.) [pt

The NuSTAR Hard X-Ray Survey of the Norma Arm Region

DEFF Research Database (Denmark)

Fornasini, Francesca M.; Tomsick, John A.; Hong, JaeSub

2017-01-01

We present a catalog of hard X-ray sources in a square-degree region surveyed by the Nuclear Spectroscopic Telescope Array (NuSTAR) in the direction of the Norma spiral arm. This survey has a total exposure time of 1.7 Ms, and the typical and maximum exposure depths are 50 ks and 1 Ms, respectively...... model with kT ≈ 15 keV, as observed for the CV candidates....

Cascaded Ga1-xAlxAs/GaAs solar cell with graded i-region

Science.gov (United States)

Mil'shtein, Sam; Halilov, Samed

2018-02-01

In current study we designed p-i-n junction with extended intrinsic layer, where linearly graded Alx Ga1-x As presents variable energy gap so needed for effective harvesting of sun radiation. The design realization involves two regions of compositional structure in the stacking direction. The top AlxGa1-xAs layer of 1 um total thickness has stoichiometric structure x=0.3-0.2d, where depth d runs from 0 to 1 um, topmost 200 nm of which is Be-doped. Bottom AlxGa1-xAs layer of 3 um total thickness has a variable composition of x=0.133-0.033d, d runs from 1 to 4 um, the very bottom of which with 10 nm thickness is Si-doped. On the top surface, there is a 50 nm layer of p+ doped GaAs as a spacer for growing AuGe/Ni anode electrode of 20% surface area, the bottom is coated with AuGe/Ni cathode electrode. The designed cell demonstrates 89% fill factor and 30% conversion efficiency without anti-reflection coating.

Detailed EXOSAT and optical observations of the intermediate polar 3A0729+103: discovery of two medium energy X-ray emission regions

International Nuclear Information System (INIS)

McHardy, I.M.; Pye, J.P.; Fairall, A.P.; Menzies, J.W.

1987-01-01

EXOSAT observations of the intermediate polar cataclysmic variable 3A0729+103 reveal a strong orbital modulation, with the 2-4KeV X-rays being significantly more modulated than the 4-6keV X-rays, indicative of photoelectric absorption. The 913 second modulation which is very prominent in the optical light curve, is weakly detected in the medium-energy X-ray light curve, confirming that it represents the white dwarf spin period. These observations are well explained by a combination of two sources of medium-energy X-ray emission. The presence of two emission regions is also clearly seen in the optical spectroscopy, particularly in the intensity of the He II4686 line which has two peaks during the orbit. The authors identify the two optical emission regions with the two X-ray emission regions. (author)

X-ray-induced specific-locus mutations in the ad-3 region of two-component heterokaryons of Neurospora crass

International Nuclear Information System (INIS)

De Serres, F.J.

1990-01-01

More extensive complementation tests than those performed initially on a series of 832 X-ray-induced specific-locus mutations in the adenine-4 (ad-3) region of a two-component heterokaryon (H-12) of Neurospora crassa showed that unexpectedly high frequencies of specific-locus mutations in the ad-3 region have additional, but separate, sites of recessive lethal damage in the immediately adjacent genetic regions. In the present paper, X-ray-induced irreparable ad-3 mutants of the folowing genotypes and numbers (ad-3A ad-3B, ad-3A ad-3B nic-2, and ad-3B nic-2) have also subjected to the same genetic fine structure analysis. These experiments, in the previous and present papers, were designed to determine the extent of the functional inactivation in the ad-3 and immediately adjacent genetic regions in individual mutants classified as presumptive multilocus deletions or multiplelocus mutations. The data in the present paper have shown that in Neurospora crassa most X-ray-induced irreparable mutants of genotype ad-3A ad-3B, ad-3A ad-3B nic-2, and ad-3 nic-2 map as a series of overlapping multilocus deletions. In addition, genetic fine structure analysis has shown that some of the mutants classified, initially, as multilocus deletions, are actually multiple-locus mutations: multilocus deletions with closely linked, and separate, sites of recessive lethal damage with a wide variety of genotyes. Combining data from the present experiments with previously published date, the frequency of multiple-locus mutations among X-ray-induced gene/point mutations and multilocus deletions in the ad-3 region is 6.2%. (author). 27 refs.; 4 figs.; 7 tab

Photoluminescence of Eu{sup 2+}-doped CaMgSi{sub 2x}O{sub 6+2x} (1.00{<=}x{<=}1.20) phosphors in UV-VUV region

Energy Technology Data Exchange (ETDEWEB)

Zhang Zhiya [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang Yuhua [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)], E-mail: wyh@lzu.edu.cn

2008-03-15

Alkaline-earth silicate phosphors CaMgSi{sub 2x}O{sub 6+2x}:Eu{sup 2+} (1.00{<=}x{<=}1.20) were prepared by traditional solid-state reaction. The phosphors showed an intense blue emission centered around 453 nm, with both 254 and 147 nm excitations. The host absorption below 200 nm in the excitation spectra consisted of two bands around 160 and 190 nm. The band around 160 nm was ascertained to be associated with the SiO{sub 4}-tetrahedra and MgO{sub 6}-polyhedra, and that around 190 nm was due to the CaO{sub 8}-polyhedra or some impurities. The incorporation of excess Si of less than 15% would not lead to formation of impurities and the results indicated that an appropriate Si excess could improve the Photoluminescence (PL) intensity in both ultraviolet (UV) and vacuum ultraviolet (VUV) regions.

Very high resolution UV and x-ray spectroscopy and imagery of solar active regions. Final report

International Nuclear Information System (INIS)

Bruner, M.; Brown, W.A.; Haisch, B.M.

1987-01-01

A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft x-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the x-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical x-ray observations using this new technique

Extending synchrotron-based atomic physics experiments into the hard X-ray region

International Nuclear Information System (INIS)

LeBrun, T.

1996-01-01

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution the authors discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. They close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells

X-Ray Emission from the Nuclear Region of Arp 220

Science.gov (United States)

Paggi, Alessandro; Fabbiano, Giuseppina; Risaliti, Guido; Wang, Junfeng; Karovska, Margarita; Elvis, Martin; Maksym, W. Peter; McDowell, Jonathan; Gallagher, Jay

2017-05-01

We present an imaging and spectral analysis of the nuclear region of the ultraluminous infrared galaxy merger of Arp 220, using deep Chandra-ACIS observations summing up to ˜ 300 {{ks}}. Narrowband imaging with subpixel resolution of the innermost nuclear region reveals two distinct Fe-K emitting sources, coincident with the infrared and radio nuclear clusters. These sources are separated by 1‧ (˜380 pc). The X-ray emission is extended and elongated in the eastern (E) nucleus, like the disk emission observed in millimeter radio images, suggesting a starburst dominance in this region. We estimate an Fe-K equivalent width of ≳ 1 {keV} for both sources and observe 2-10 keV luminosities of ˜ 2× {10}40 {{erg}} {{{s}}}-1 (western, W) and ˜ 3× {10}40 {{erg}} {{{s}}}-1 (E). In the 6-7 keV band the emission from these regions is dominated by the 6.7 keV Fe xxv line, suggesting a contribution from collisionally ionized gas. The thermal energy content of this gas is consistent with the kinetic energy injection in the interstellar medium by SNe II. However, nuclear winds from a hidden active galactic nucleus (AGN) (\\upsilon ˜ 2000 {{km}} {{{s}}}-1) cannot be excluded. The 3σ upper limits on the neutral Fe-Kα flux of the nuclear regions correspond to the intrinsic AGN 2-10 keV luminosities of < 1× {10}42 {{erg}} {{{s}}}-1 (W) and < 0.4× {10}42 {{erg}} {{{s}}}-1 (E). For typical AGN spectral energy distributions the bolometric luminosities are < 3× {10}43 {{erg}} {{{s}}}-1 (W) and < 8× {10}43 {{erg}} {{{s}}}-1 (E), and black hole masses of < 1× {10}5 {M}⊙ (W) and < 5× {10}5 {M}⊙ (E) are evaluated for Eddington limited AGNs with a standard 10% efficiency.

The gamma-ray emitting region of the jet in Cyg X-3

Science.gov (United States)

Zdziarski, Andrzej A.; Sikora, Marek; Dubus, Guillaume; Yuan, Feng; Cerutti, Benoit; Ogorzałek, Anna

2012-04-01

We study models of the γ-ray emission of Cyg X-3 observed by Fermi. We calculate the average X-ray spectrum during the γ-ray active periods. Then, we calculate spectra from Compton scattering of a photon beam into a given direction by isotropic relativistic electrons with a power-law distribution, both based on the Klein-Nishina cross-section and in the Thomson limit. Applying the results to scattering of stellar blackbody radiation in the inner jet of Cyg X-3, we find that a low-energy break in the electron distribution at a Lorentz factor of ˜300-103 is required by the shape of the observed X-ray/γ-ray spectrum in order to avoid overproducing the observed X-ray flux. The electrons giving rise to the observed γ-rays are efficiently cooled by Compton scattering, and the power-law index of the acceleration process is ≃2.5-3. The bulk Lorentz factor of the jet and the kinetic power before the dissipation region depend on the fraction of the dissipation power supplied to the electrons; if it is ≃1/2, the Lorentz factor is ˜2.5, and the kinetic power is ˜1038 erg s-1, which represents a firm lower limit on the jet power, and is comparable to the bolometric luminosity of Cyg X-3. Most of the power supplied to the electrons is radiated. The broad-band spectrum constrains the synchrotron and self-Compton emission from the γ-ray emitting electrons, which requires the magnetic field to be relatively weak, with the magnetic energy density ≲ a few times 10-3 of that in the electrons. The actual value of the magnetic field strength can be inferred from a future simultaneous measurement of the infrared and γ-ray fluxes.

NuSTAR Search for Hard X-ray Emission from the Star Formation Regions in Sh2-104

Science.gov (United States)

Gotthelf, Eric V.

2016-04-01

We present NuSTAR hard X-ray observations of Sh2-104, a compact Hii region containing several young massive stellar clusters (YMSCs). We have detected distinct hard X-ray sources coincident with localized VERITAS TeV emission recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. Faint, diffuse X-ray emission coincident with the eastern YMSC in Sh2-104 is likely the result of colliding winds of component stars. Just outside the radio shell of Sh2-104 lies 3XMM J201744.7+365045 and nearby nebula NuSTAR J201744.3+364812, whose properties are most consistent with extragalactic objects. The combined XMM-Newton and NuSTAR spectrum of 3XMM J201744.7+365045 is well-fit to an absorbed power-law model with NH = (3.1+/-1.0)E22 1/cm^2 and photon index Gamma = 2.1+/-0.1. Based on possible long-term flux variation and lack of detected pulsations (Sh2-104 will help identify the nature of the X-ray sources and their relation to MGRO J2019+37.

Calibration technique for radiation measurements in vacuum ultraviolet - soft x-ray region

International Nuclear Information System (INIS)

Mizui, Jun-ichi

1986-05-01

This is a collection of the papers presented at the workshop on ''Calibration Technique for Radiation Measurements in Vacuum Ultraviolet - Soft X-ray Region'' held at the Institute of Plasma Physics, Nagoya University, on December 19 - 20, 1985, under the Collaborating Research Program at the Institute. The following topics were discussed at the workshop: the needs for the calibration of plasma diagnostic devices, present status of the calibration technique, use of the Synchrotron Orbit Radiations for radiometry, and others. (author)

Interstitial deletion in the "critical region" of the long arm of the X chromosome in a mentally retarded boy and his normal mother

DEFF Research Database (Denmark)

Tabor, A; Andersen, O; Lundsteen, C

1983-01-01

A family in which an intestitial deletion of the X chromosome, del(X)(q13q21.3), is segregating was ascertained through a boy with cleft lip and palate, agenesis of the corpus callosum, and severe mental retardation. The possible causal relationship to his chromosome abnormality is discussed. Alt....... Although the deletion occurred within the critical region, the mother showed no signs of gonadal dysgenesis. A phenotypically normal daughter was, as her mother, monosomic for this region of the X, and both showed random inactivation of the X chromosome....

NuSTAR HARD X-RAY SURVEY OF THE GALACTIC CENTER REGION. I. HARD X-RAY MORPHOLOGY AND SPECTROSCOPY OF THE DIFFUSE EMISSION

Energy Technology Data Exchange (ETDEWEB)

Mori, Kaya; Hailey, Charles J.; Perez, Kerstin; Nynka, Melania; Zhang, Shuo; Canipe, Alicia M. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Krivonos, Roman; Tomsick, John A.; Barrière, Nicolas; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Hong, Jaesub [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Ponti, Gabriele [Max-Planck-Institut f. extraterrestrische Physik, HEG, Garching (Germany); Bauer, Franz [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Alexander, David M. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Baganoff, Frederick K. [Kavli Institute for Astrophysics and Space Research, Massachusets Institute of Technology, Cambridge, MA 02139 (United States); Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Christensen, Finn E. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Forster, Karl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Giommi, Paolo, E-mail: kaya@astro.columbia.edu [ASI Science Data Center, Via del Politecnico snc I-00133, Roma (Italy); and others

2015-12-01

We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). NuSTAR detects four non-thermal X-ray filaments, extending the detection of their power-law spectra with Γ ∼ 1.3–2.3 up to ∼50 keV. A morphological and spectral study of the filaments suggests that their origin may be heterogeneous, where previous studies suggested a common origin in young pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission spatially correlated with the 6.4 keV Fe Kα fluorescence line emission associated with two Sgr A molecular clouds: MC1 and the Bridge. Broadband X-ray spectral analysis with a Monte-Carlo based X-ray reflection model self-consistently determined their intrinsic column density (∼10{sup 23} cm{sup −2}), primary X-ray spectra (power-laws with Γ ∼ 2) and set a lower limit of the X-ray luminosity of Sgr A* flare illuminating the Sgr A clouds to L{sub X} ≳ 10{sup 38} erg s{sup −1}. Above ∼20 keV, hard X-ray emission in the central 10 pc region around Sgr A* consists of the candidate PWN G359.95–0.04 and the CHXE, possibly resulting from an unresolved population of massive CVs with white dwarf masses M{sub WD} ∼ 0.9 M{sub ⊙}. Spectral energy distribution analysis suggests that G359.95–0.04 is likely the hard X-ray counterpart of the ultra-high gamma-ray source HESS J1745–290, strongly favoring a leptonic origin of the GC TeV emission.

Characterization of a panel of somatic cell hybrids for regional mapping of the mouse X chromosome

International Nuclear Information System (INIS)

Avner, P.; Arnaud, D.; Amar, L.; Cambrou, J.; Winking, H.; Russell, L.B.

1987-01-01

A panel of five hybrid cell lines containing mouse X chromosomes with various deletions has been obtained by fusing splenocytes from male mice carrying one of a series of reciprocal X-autosome translocations with the azaguanine-resistant Chinese hamster cell line CH3g. These hybrids have been extensively characterized by using the allozymes hypoxanthine/guanine phosphoribosyltransferase (encoded by the Hprt locus) and α-galactosidase (Ags) and a series of 11 X-chromosome-specific DNA probes whose localization had been previously established by linkage studies. Such studies have established the genetic breakpoints of the T(X;12)13R1 and T(X;2)14R1 X-autosome translocations on the X chromosome and provided additional information as to the X-chromosome genetic breakpoints of the T(X;16)16H, T(X;4)7R1, and T(X;7)6R1 translocations. The data establish clearly that both the T(X;7)5RI and T(X;12)13R1 X-chromosome breakpoints are proximal to Hprt, the breakpoint of the former being more centromeric, lying as it does in the 9-centimorgan interval between the ornithine transcarbamoylase (Otc) and DXPas7 (M2C) loci. These five hybrid cell lines provide, with the previously characterized EBS4 hybrid cell line, a nested series of seven mapping intervals distributed along the length of the mouse X chromosome. Their characterization not only allows further correlation of the genetic and cytological X-chromosome maps but also should permit the rapid identification of DNA probes specific for particular regions of the mouse X chromosome

X-RAY EMISSION FROM YOUNG STARS IN THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

International Nuclear Information System (INIS)

Anderson, C. N.; Hofner, P.; Creech-Eakman, M.; Shepherd, D.

2011-01-01

We present a 40 ks Chandra observation of the IRAS 20126+4104 core region. In the inner 6'' two X-ray sources were detected, which are coincident with the radio jet source I20S and the variable radio source I20Var. No X-ray emission was detected from the nearby massive protostar I20N. The spectra of both detected sources are hard and highly absorbed, with no emission below 3 keV. For I20S, the measured 0.5-8 keV count rate was 4.3 counts ks -1 . The X-ray spectrum was fitted with an absorbed 1T APEC model with an energy of kT =10 keV and an absorbing column of N H = 1.2 x 10 23 cm -2 . An unabsorbed X-ray luminosity of about 1.4 x 10 32 erg s -1 was estimated. The spectrum shows broad line emission between 6.4 and 6.7 keV, indicative of emission from both neutral and highly ionized iron. The X-ray light curve indicates that I20S is marginally variable; however, no flare emission was observed. The variable radio source I20Var was detected with a count rate of 0.9 counts ks -1 but there was no evidence of X-ray variability. The best-fit spectral model is a 1T APEC model with an absorbing hydrogen column of N H = 1.1 x 10 23 cm -2 and a plasma energy of kT = 6.0 keV. The unabsorbed X-ray luminosity is about 3 x 10 31 erg s -1 .

Design and characterization for absolute x-ray spectrometry in the 100-10,000 eV region

International Nuclear Information System (INIS)

Henke, B.L.

1986-08-01

Reviewed here are the design and characterization procedures used in our program for developing absolute x-ray spectrometry in the 100 to 10,000 eV region. Described are the selection and experimental calibration of the x-ray filters, mirror momochromators, crystal/multilayer analyzers, and the photographic (time integrating) and photoelectric (time resolving) position-sensitive detectors. Analytical response functions have been derived that characterize the energy dependence of the mirror and crystal/multilayer reflectivities and of the photographic film and photocathode sensitivities. These response functions permit rapid, small-computer reduction of the experimental spectra to absolute spectra (measured in photons per stearadian from the source for radiative transitions at indicated photon energies). Our x-ray spectrographic systems are being applied to the diagnostics of pulsed, high temperature plasma sources in laser fusion and x-ray laser research. 15 refs., 27 figs

Spin asymmetries $A_1$ of the proton and the deuteron in the low $x$ and low $Q^2$ region from polarized high energy muon scattering

CERN Document Server

AUTHOR|(CDS)2067425; Arvidson, A; Badelek, B; Baum, G; Berglund, P; Betev, L; De Botton, N R; Bradamante, Franco; Bravar, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krämer, Dietrich; Kröger, W; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Piegaia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Reicherz, G; Roberts, J; Rodríguez, M; Rondio, Ewa; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Willumeit, R; Windmolders, R; Wislicki, W; Witzmann, A; Zanetti, A M; Zaremba, K; Zhao, J

1999-01-01

We present the results of the spin asymmetries $A_1$ of the proton and the deuteron in the kinematic region extending down to $x=6\\cdot 10^{-5}$ and $Q^2=0.01$ GeV$^2$. The data were taken with a dedicated low $x$ trigger, which required hadron detection in addition to the scattered muon, so as to reduce the background at low $x$. The results complement our previous measurements and the two sets are consistent in the overlap region. No sig\\-ni\\-fi\\-cant spin effects are found in the newly explored region.

Absence of methylation of a CpG-rich region at the 5' end of the MIC2 gene on the active X, the inactive X, and the Y chromosome

International Nuclear Information System (INIS)

Goodfellow, P.J.; Mondello, C.; Darling, S.M.; Pym, B.; Little, P.; Goodfellow, P.N.

1988-01-01

The authors have identified and characterized a Hpa II tiny fragment (HTF) island associated with the promoter region of the pseudoautosomal gene MIC2. The MIC2 HTF island is unmethylated on both the active and inactive X chromosome and is similarly unmethylated on the Y chromosome. Unlike the majority of genes borne on the X chromosome, MIC2 fails to undergo X chromosome inactivation. HTF islands associated with X chromosome-liked genes that are inactivated are highly methylated on the inactive or transcriptionally silent homologue. The failure of MIC2 to undergo X chromosome inactivation correlates with the lack of methylation of HTF island at the 5' end of the gene. These results provide further evidence that DNA methylation plays an important role in the phenomenon of X chromosome inactivation

Temporal characterization and regional contribution to O{sub 3} and NO{sub x} at an urban and a suburban site in Nanjing, China

Energy Technology Data Exchange (ETDEWEB)

Xie, Min, E-mail: minxie@nju.edu.cn; Zhu, Kuanguang; Wang, Tijian, E-mail: tjwang@nju.edu.cn; Chen, Pulong; Han, Yong; Li, Shu; Zhuang, Bingliang; Shu, Lei

2016-05-01

To improve our understanding of the interplay among local and regional photochemical pollutants in the typical city of the Yangtze River Delta (YRD) region, the concurrent observation of O{sub 3} and NO{sub x} concentrations at an urban and a suburban site in Nanjing during 2008 is presented. In general, the annual mean O{sub 3} concentration is 2.35 ppbv lower in the downtown than at suburban due to higher NO{sub x} pollution levels correlated with heavy traffic. At both sites, O{sub 3} shows a distinct seasonality with the spring maximum and the winter minimum, while the minimum concentration of NO{sub x} appears in summertime. Besides the chemical processes of O{sub 3} sensitivity in the daytime and the NO{sub x} titration at night, meteorological conditions also play an essential role in these monthly and diurnal variations. The ozone weekend effect that can be attributed to the weekly routine of human activities is observed in the urban atmosphere of Nanjing as well, with O{sub 3} concentrations 2.09 ppbv higher and NO{sub x} concentrations 6.20 ppbv lower on weekends than on weekdays. The chemical coupling of NO, NO{sub 2} and O{sub 3} is investigated to show that the OX-component (O{sub 3} and NO{sub 2}) partitioning point occurs at about 35 ppbv for NO{sub x}, with O{sub 3} being the dominant form at lower levels and NO{sub 2} dominating at higher levels. And it is also discovered that the level of OX is made up of two contributions, including the regional contribution affected by regional background O{sub 3} level and the local contribution correlated with the level of primary pollution. The diurnal peak of regional contribution appears 2–5 h after the peak of local contribution, implying that OX in Nanjing might prominently affected by the pollutants from a short distance. The highest regional contribution and the second highest local contribution lead to the spring peak of O{sub 3} observed in Nanjing, whereas the highest local contribution and the

Short term variation of Cyg X-1 in the hard x-ray region

International Nuclear Information System (INIS)

Doi, Kosei

1978-01-01

Cyg X-1 is a peculiar celestial body considered to be a close binary system of a black hole and a blue super-giant star. It is presently known that the time fluctuation of Cyg X-1 is considerably complex, ranging from seconds to days or months. Of these variation, attention has been paid to the short time variation in relation to the black hole theory. Observations of fluctuations in the order of second have been limited to soft X-ray (20 keV or more) so far, because great technical difficulties are involved due to the low intensity of hard X-ray. The present investigation is based on the fluctuations in the order of second in hard X-ray, and was conducted by employing an unprecedented large area X-ray telescope. The text describes on the brief history of the short time fluctuation, explains the experimental plan, X-ray detecting system, flight of a balloon and the analyses and discussions of fluctuation factor by variation function method, and gives the analysis data and conclusion. The observations resulted in the fact that the fluctuations in the order of second were small at 20 to 30 keV, but become large when energy is higher or lower than this value. The most natural explanation available for this result may be that it is essentially spectrum fluctuation, being inverse correlation in higher and lower energies. Physical meaning of such spectrum fluctuation is considered in connection with precipitating disk model around a black hole. (Wakatsuki, Y.)

Short term variation of Cyg X-1 in the hard x-ray region

Energy Technology Data Exchange (ETDEWEB)

Doi, Kosei [Tokyo Univ. (Japan). Inst. of Space and Aeronautical Science

1978-08-01

Cyg X-1 is a peculiar celestial body considered to be a close binary system of a black hole and a blue super-giant star. It is presently known that the time fluctuation of Cyg X-1 is considerably complex, ranging from seconds to days or months. Of these variation, attention has been paid to the short time variation in relation to the black hole theory. Observations of fluctuations in the order of second have been limited to soft X-ray (20 keV or more) so far, because great technical difficulties are involved due to the low intensity of hard X-ray. The present investigation is based on the fluctuations in the order of second in hard X-ray, and was conducted by employing an unprecedented large area X-ray telescope. The text describes on the brief history of the short time fluctuation, explains the experimental plan, X-ray detecting system, flight of a balloon and the analyses and discussions of fluctuation factor by variation function method, and gives the analysis data and conclusion. The observations resulted in the fact that the fluctuations in the order of second were small at 20 to 30 keV, but become large when energy is higher or lower than this value. The most natural explanation available for this result may be that it is essentially spectrum fluctuation, being inverse correlation in higher and lower energies. Physical meaning of such spectrum fluctuation is considered in connection with precipitating disk model around a black hole.

AN X-RAY SURVEY OF THE YOUNG STELLAR POPULATION OF THE LYNDS 1641 AND IOTA ORIONIS REGIONS

Energy Technology Data Exchange (ETDEWEB)

Pillitteri, I.; Wolk, S. J.; Myers, P.; Walter, F. [SAO-Harvard Center for Astrophysics, Cambridge, MA 02138 (United States); Megeath, S. T. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Allen, L. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Bally, J. [University of Colorado, Boulder, CO 80309 (United States); Gagne, M. [Department of Geology and Astronomy, West Chester University, West Chester, PA 19383 (United States); Gutermuth, R. A. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Hartman, L. [University of Michigan, Ann Arbor, MI 48109 (United States); Micela, G.; Sciortino, S. [INAF-Osservatorio Astronomico di Palermo, I-90134 Palermo (Italy); Oliveira, J. M. [School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Rebull, L.; Stauffer, J., E-mail: ipillitteri@cfa.harvard.edu [CALTECH, Pasadena, CA 91125 (United States)

2013-05-10

We present an XMM-Newton survey of the part of the Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star {iota} Orionis. In addition to proprietary data, we used archival XMM data of the Orion Nebula Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud. We have detected 1060 X-ray sources in L1641 and the {iota} Ori region. About 94% of the sources have Two Micron All Sky Survey and Spitzer counterparts, 204 and 23 being Class II and Class I or protostar objects, respectively. In addition, we have identified 489 X-ray sources as counterparts to Class III candidates, given they are bright in X-rays and appear as normal photospheres at mid-IR wavelengths. The remaining 205 X-ray sources are likely distant active galactic nuclei or other galactic sources not related to Orion A. We find that Class III candidates appear more concentrated in two main clusters in L1641. The first cluster of Class III stars is found toward the northern part of L1641, concentrated around {iota} Ori. The stars in this cluster are more evolved than those in the Orion Nebula. We estimate a distance of 300-320 pc for this cluster showing that it is in the foreground of the Orion A cloud. Another cluster rich in Class III stars is located in L1641 South and appears to be a slightly older cluster embedded in the Orion A cloud. Furthermore, other evolved Class III stars are found north of the ONC toward NGC 1977.

AN X-RAY SURVEY OF THE YOUNG STELLAR POPULATION OF THE LYNDS 1641 AND IOTA ORIONIS REGIONS

International Nuclear Information System (INIS)

Pillitteri, I.; Wolk, S. J.; Myers, P.; Walter, F.; Megeath, S. T.; Allen, L.; Bally, J.; Gagné, M.; Gutermuth, R. A.; Hartman, L.; Micela, G.; Sciortino, S.; Oliveira, J. M.; Rebull, L.; Stauffer, J.

2013-01-01

We present an XMM-Newton survey of the part of the Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star ι Orionis. In addition to proprietary data, we used archival XMM data of the Orion Nebula Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud. We have detected 1060 X-ray sources in L1641 and the ι Ori region. About 94% of the sources have Two Micron All Sky Survey and Spitzer counterparts, 204 and 23 being Class II and Class I or protostar objects, respectively. In addition, we have identified 489 X-ray sources as counterparts to Class III candidates, given they are bright in X-rays and appear as normal photospheres at mid-IR wavelengths. The remaining 205 X-ray sources are likely distant active galactic nuclei or other galactic sources not related to Orion A. We find that Class III candidates appear more concentrated in two main clusters in L1641. The first cluster of Class III stars is found toward the northern part of L1641, concentrated around ι Ori. The stars in this cluster are more evolved than those in the Orion Nebula. We estimate a distance of 300-320 pc for this cluster showing that it is in the foreground of the Orion A cloud. Another cluster rich in Class III stars is located in L1641 South and appears to be a slightly older cluster embedded in the Orion A cloud. Furthermore, other evolved Class III stars are found north of the ONC toward NGC 1977.

X irradiation combined with TNF alpha-related apoptosis-inducing ligand (TRAIL) reduces hypoxic regions of human gastric adenocarcinoma xenografts in SCID mice

International Nuclear Information System (INIS)

Takahashi, Momoko; Yasui, Hironobu; Ogura, Aki; Asanuma, Taketoshi; Inanami, Osamu; Kubota, Nobuo; Tsujitani, Michihiko; Kuwabara, Mikinori

2008-01-01

Our previous study showed that X irradiation induced the expression of death receptor DR5 on the cell surface in tumor cell lines under not only normoxia but also hypoxia. X irradiation combined with TNF α-related apoptosis-inducing ligand (TRAIL), which is the ligand of DR5, induced apoptosis in vitro (Takahashi et al., (2007) Journal of Radiation Research, 48: 461-468). In this report, we examined the in vivo antitumor efficacy of X irradiation combined with TRAIL treatment in tumor xenograft models derived from human gastric adenocarcinoma MKN45 and MKN28 cells in severe combined immunodeficiency (SCID) mice. X irradiation combined with TRAIL synergistically suppressed the tumor growth rates in the xenograft models derived from MKN45 and MKN28 cells, which have wild type Tp53 and mutated Tp53, respectively, indicating that the antitumor effects occurred in a Tp53-independent manner. Histological analysis showed that the combination of X irradiation and TRAIL induced caspase-3-dependent apoptotic cell death. Moreover, the immunohistochemical detection of hypoxic regions using the hypoxic marker pimonidazole revealed that caspase-3-dependent apoptosis occurred in the hypoxic regions in the tumors. These results indicated that X irradiation combined with TRAIL may be a useful treatment to reduce tumor growth in not only normoxic but also hypoxic regions. (author)

Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region

International Nuclear Information System (INIS)

Kleinfelder, Stuart; Bichsel, Hans; Bieser, Fred; Matis, Howard S.; Rai, Gulshan; Retiere, Fabrice; Weiman, Howard; Yamamoto, Eugene

2002-01-01

Integrated CMOS Active Pixel Sensor (APS) arrays have been fabricated and tested using X-ray and electron sources. The 128 by 128 pixel arrays, designed in a standard 0.25 micron process, use a ∼10 micron epitaxial silicon layer as a deep detection region. The epitaxial layer has a much greater thickness than the surface features used by standard CMOS APS, leading to stronger signals and potentially better signal-to-noise ratio (SNR). On the other hand, minority carriers confined within the epitaxial region may diffuse to neighboring pixels, blur images and reduce peak signal intensity. But for low-rate, sparse-event images, centroid analysis of this diffusion may be used to increase position resolution. Careful trade-offs involving pixel size and sense-node area verses capacitance must be made to optimize overall performance. The prototype sensor arrays, therefore, include a range of different pixel designs, including different APS circuits and a range of different epitaxial layer contact structures. The fabricated arrays were tested with 1.5 GeV electrons and Fe-55 X-ray sources, yielding a measured noise of 13 electrons RMS and an SNR for single Fe-55 X-rays of greater than 38

THE STRUCTURE OF THE X-RAY AND OPTICAL EMITTING REGIONS OF THE LENSED QUASAR Q 2237+0305

International Nuclear Information System (INIS)

Mosquera, A. M.; Kochanek, C. S.; Blackburne, J. A.; Chen, B.; Dai, X.; Chartas, G.

2013-01-01

We use gravitational microlensing to determine the size of the X-ray and optical emission regions of the quadruple lens system Q 2237+0305. The optical half-light radius, log(R 1/2,V /cm) = 16.41 ± 0.18 (at λ rest = 2018 Å), is significantly larger than the observed soft, log(R 1/2,soft /cm)=15.76 +0.41 -0.34 (1.1-3.5 keV in the rest frame), and hard, log(R 1/2,hard /cm)=15.46 +0.34 -0.29 (3.5-21.5 keV in the rest frame), band X-ray emission. There is weak evidence that the hard component is more compact than the soft, with log(R 1/2,soft /R 1/2,hard )≅0.30 +0.53 -0.45 . This wavelength-dependent structure agrees with recent results found in other lens systems using microlensing techniques, and favors geometries in which the corona is concentrated near the inner edge of the accretion disk. While the available measurements are limited, the size of the X-ray emission region appears to be roughly proportional to the mass of the central black hole.

Construction of a forensic soil database of the Hokkaido region in Japan by synchrotron radiation X-ray analysis

International Nuclear Information System (INIS)

Shirota, Yusuke; Hirao, Masataka; Abe, Yoshinari; Nakai, Izumi; Osaka, Keiichi; Itou, Masayoshi

2017-01-01

The purpose of the present study is to construct a nation-wide forensic soil database, which allows for the identification of soil evidence based on heavy element and heavy mineral signatures determined by two synchrotron radiation (SR) X-ray techniques, i.e., a high-energy synchrotron radiation X-ray fluorescence analysis and a synchrotron-radiation X-ray powder diffraction analysis, respectively. The heavy element and heavy mineral compositions of the stream sediments collected at 3024 points located all over Japan were measured by the two SR X-ray techniques. The present paper focuses on a regional characterization of the sediments collected from the Hokkaido areas. The concentrations of heavy elements and heavy minerals in the Hokkaido areas were visualized as maps that enable us to compare the heavy element and heavy mineral compositions with the geological context of the samples. Based on a hierarchical cluster analysis using the semi-quantitative compositions of the heavy minerals, we could successfully classify the sediments into six groups corresponding to their background geologies. A Bonferroni multiple comparison demonstrated that these six groups also have significant differences in the heavy element composition. From these examinations, we could demonstrate that detailed regional identification of unknown samples is possible by analyzing both heavy element and heavy mineral compositions of each sample. (author)

Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the MPB region of (1-x)Bi(Mg_1_/_2Ti_1_/_2)O_3_-_xPbTiO_3

International Nuclear Information System (INIS)

Upadhyay, A.; Singh, A.K.

2016-01-01

The results of the room temperature structural studies on (1-x)Bi(Mg_1_/_2Ti_1_/_2)O_3_-_xPbTiO_3 ceramics using Rietveld analysis of the powder X-ray diffraction data in the composition range 0.28≤x≤0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4mm) phases in the composition range 0.33≤x≤0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28≤x≤0.32. The structure for the compositions with x≥0.45 is found to be predominantly tetragonal with space group P4mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x=0.35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size. (author)

Analysis of Precious Stones Deposited in Various Rock Samples of Mogok Region by energy dispersive X-ray Fluorescence Spectrometry

International Nuclear Information System (INIS)

Kyi Kyi San; Soe Lwin; Win Win Thar; Sein Htoon

2004-06-01

The analysis of precious stones deposited in various rock samples of Mogok region were investigated by the energy dispersive x-ray fluorescence technique. The x-ray machine with Rh target was used to excite the characteristic x-ray from the sample. X-rays emitted from the sample were measured by a high resolution, cooled Si (Li) detector. The calibration was made by the measurement of minerals which composed in each kind of precious stones. The kind of precious stone deposited in the rocks sample was determined by the measurement of minerals from the rock samples compared with those obtained from each kind of precious stones

Analysis of the Relationship Between the Solar X-Ray Radiation Intensity and the D-Region Electron Density Using Satellite and Ground-Based Radio Data

Science.gov (United States)

Nina, Aleksandra; Čadež, Vladimir M.; Bajčetić, Jovan; Mitrović, Srdjan T.; Popović, Luka Č.

2018-04-01

Increases in the X-ray radiation that is emitted during a solar X-ray flare induce significant changes in the ionospheric D region. Because of the numerous complex processes in the ionosphere and the characteristics of the radiation and plasma, the causal-consequential relationship between the X-ray radiation and ionospheric parameters is not easily determined. In addition, modeling the ionospheric D-region plasma parameters is very difficult because of the lack of data for numerous time- and space-dependent physical quantities. In this article we first give a qualitative analysis of the relationship between the electron density and the recorded solar X-ray intensity. After this, we analyze the differences in the relationships between the D-region response and various X-ray radiation properties. The quantitative study is performed for data observed on 5 May 2010 in the time period between 11:40 UT - 12:40 UT when the GOES 14 satellite detected a considerable X-ray intensity increase. Modeling the electron density is based on characteristics of the 23.4 kHz signal emitted in Germany and recorded by the receiver in Serbia.

The LHC can probe small x PDFs; the treatment of the infrared region

International Nuclear Information System (INIS)

Martin, A. D.; De Oliveira, E. G.; Ryskin, M. G.

2013-01-01

First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements of parton distribution functions in the low x domain; x≲10 −4 . Second, we find an inconsistency in the conventional NLO treatment of the infrared region. We illustrate the problem using the NLO coefficient function of Drell-Yan production.

X-ray tube

International Nuclear Information System (INIS)

Webley, R.S.

1975-01-01

The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

Optical properties of La2CuO4 and La2−xCaxCuO4 crystallites in UV–vis–NIR region synthesized by sol–gel process

International Nuclear Information System (INIS)

Li Yifeng; Huang Jianfeng; Cao Liyun; Wu Jianpeng; Fei Jie

2012-01-01

La 2 CuO 4 and La 2−x Ca x CuO 4 crystallites were prepared via a simple sol–gel process. The as-prepared La 2 CuO 4 and La 2 −x Ca x CuO 4 crystallites were characterized by X-ray diffraction, transmission electron microscope and UV–vis–NIR spectra. Results show that the grain size of La 2 CuO 4 crystallites increases with the increase of heat treatment temperature from 600 °C to 800 °C. Optical properties show that La 2 CuO 4 crystallites have broad absorption both in the UV–vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367 eV to 1.284 eV with the increase of calcination temperature from 600 °C to 800 °C. In the series of La 2−x Ca x CuO 4 compounds (x = 0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca 2+ in La 2 CuO 4 is within the range of x = 0.12–0.15. In the whole UV–vis–NIR region, La 2−x Ca x CuO 4 crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca 2+ content. - Highlights: ► The optical band gap can be tuned by adjusting the grain size and Ca 2+ content. ► La 2 CuO 4 crystallites exhibit a broad absorption band both in the UV–vis region and in the NIR region. ► The band gap increases from 1.284 eV to 1.319 eV with the decrease of heat treatment temperature. ► In the whole UV–vis–NIR region, the La 2−x Ca x CuO 4 crystallites displayed a broad absorption. ► The band gap of La 2−x Ca x CuO 4 increases linearly with doping level when 0 ≤ x ≤ 0.12.

First ultraviolet observations of the transition regions of X-ray bright solar-type stars in the Pleiades

Science.gov (United States)

Caillault, J.-P.; Vilhu, O.; Linsky, J. L.

1990-01-01

Results are reported from A UV study of the transition regions of two X-ray-bright solar-type stars from the Pleiades, in an attempt to extend the main sequence age baseline for the transition-region activity-age relation over more than two orders of magnitude. However, no emission lines were detected from either star; the upper limits to the fluxes are consistent with previously determined saturation levels, but do not help to further constrain evolutionary models.

NNLO corrections to anti B {yields} X{sub u}l anti {nu} in the shape-function region

Energy Technology Data Exchange (ETDEWEB)

Asatrian, H.M. [Erevanskij Fizicheskij Inst., Erevan (Armenia); Greub, C. [Bern Univ. (Switzerland). Inst. for Theoretical Physics; Pecjak, B.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2008-10-15

The inclusive decay anti B {yields} X{sub u}l anti {nu} is of much interest because of its potential to constrain the CKM element vertical stroke V{sub ub} vertical stroke. Experimental cuts required to suppress charm background restrict measurements of this decay to the shape-function region, where the hadronic final state carries a large energy but only a moderate invariant mass. In this kinematic region, the differential decay distributions satisfy a factorization formula of the form H.J x S, where S is the non-perturbative shape function, and the object H.J is a perturbatively calculable hard-scattering kernel. In this paper we present the calculation of the hard function H at next-to-next-to-leading order (NNLO) in perturbation theory. Combined with the known NNLO result for the jet function J, this completes the perturbative part of the NNLO calculation for this process. (orig.)

HELIUM IN NATAL H II REGIONS: THE ORIGIN OF THE X-RAY ABSORPTION IN GAMMA-RAY BURST AFTERGLOWS

International Nuclear Information System (INIS)

Watson, Darach; Andersen, Anja C.; Fynbo, Johan P. U.; Hjorth, Jens; Krühler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele; Zafar, Tayyaba; Gorosabel, Javier; Jakobsson, Páll

2013-01-01

Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that absorption by He in the GRB's host H II region is responsible for most of the absorption. We show that the X-ray absorbing column density (N H X ) is correlated with both the neutral gas column density and with the optical afterglow's dust extinction (A V ). This correlation explains the connection between dark bursts and bursts with high N H X values. From these correlations, we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e., the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this, we conclude that the column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals. The strong redshift evolution of N H X /A V is thus a reflection of the cosmic metallicity evolution of star-forming galaxies and we find it to be consistent with measurements of the redshift evolution of metallicities for GRB host galaxies. We conclude that the absorption of X-rays in GRB afterglows is caused by He in the H II region hosting the GRB. While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionizing UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionized state. Helium X-ray absorption explains the correlation with total gas, the lack of strong evolution with redshift, as well as the absence of dust, metal or

Neutron scattering investigations of the properties of the x - T phase diagram of Rb1-x(NH4)xI mixed crystals

International Nuclear Information System (INIS)

Smirnov, L.S.; Natkaniec, I.; Savenko, B.N.

2002-01-01

The x - T phase diagram of Rb 1-x (NH 4 ) x I is studied using samples with the ammonium concentration 0.01< x<0.77 over a wide temperature region of 15 to 300 K by neutron powder diffraction and inelastic incoherent neutron scattering. The results of powder diffraction studies show that at low temperatures a phase transition from α-phase to β-phase is observed at ammonium concentrations x = 0.50 and x = 0.66. Inelastic incoherent neutron scattering detects a region of the orientional glass state at ammonium concentrations 0.29< x,0.40

Study of the CdX-B2X3-X (X=S, Se), CdTe-B-Te systems

International Nuclear Information System (INIS)

Odin, I.N.; Grin'ko, V.V.; Safronov, E.V.; Kozlovskij, V.F.

2001-01-01

Liquidus surfaces of the CdX-B 2 X 3 -X (X=S, Se), CdTe-B-Te systems are plotted for the first time. It is shown that in equilibrium solid solutions on the basis of ternary Cd 2 B 2 X 5 compounds and binary B 2 X 3 , CdX, BS 2 compounds take part with liquid phases. p gen -T and T-x projects of p-T-x phase diagram of B-S (59-100 at. % S), B-Se (59-100 at. % Se), B-Te systems are plotted . B 2 X 3 , BS 2 compounds are formed in that regions of compositions of B-X systems . In the B-Te system compounds are not formed. Ternary compounds are not formed in the CdTe-B-Te system [ru

Use of X-ray CT-defined regions of interest for the determination of SPECT recovery coefficients

International Nuclear Information System (INIS)

Tang, H.R.; Brown, J.K.; Hasegawa, B.H.

1996-01-01

For accurate activity per unit volume measurements in SPECT, recovery coefficients are usually applied based on the size and shape of objects being imaged to properly account for the resolution limitations of the gamma camera. Because of noise and limited spatial resolution, determination of object sizes and boundaries can be difficult using the SPECT images alone. We therefore have developed a technique which determines activity concentrations for SPECT using regions of interest (ROI's) obtained from coregistered X-ray CT images. In this study, experimental phantoms containing cylindrical and spherical objects were imaged on a combined X-ray CT/SPECT system and reconstructed data volumes were registered using the known geometry of the system. ROI's were defined on the registered CT images and used to help quantify activity concentration in localized regions and to measure object volumes. We have derived the recovery curves for these objects and scan technique. We have also tested a technique that demonstrates activity quantitation without the need for object and size dependent recovery coefficients in the case of low background

Evaluation of regional pulmonary ventilation by videodensitometry using a new X-ray image processor

International Nuclear Information System (INIS)

Fujii, Tadashige; Kanai, Hisakata; Handa, Kenjiro; Takizawa, Masaomi

1988-01-01

A new video image processing device has been produced in order to assess regional pulmonary ventilation. This device consists of a microcomputer, digital frame memory, digitizer, videomonitor, joystick and videotape recorder. The changing radiographic density of the lungs during deep respiration and forced expiration is recorded by the videotape recorder, which is connected to an image intensifier television system. This device allows the examining physician to place 6 rectangular windows of variable size over any portion of the video image using the joystick, and to measure the brightness level within these windows simultaneously. It is very characteristic that the video-densitometric curve and marks of the windows are superimposed on the frozen final frame of the sampled images. By this procedure, fair videodensigrams were obtained in various respiratory diseases, and reduction of ventilatory amplitude was shown in the hypoventilatory regions. The joint use of video-densitometry and perfusion lung scintigraphy provided helpful information concerning the regional ventilation/perfusion relationship. The videodensitometry of the lung the new X-ray image processor offers routine screening evaluation of regional pulmonary ventilation abnormalities over the entire video image of the lungs without more effort required of the patients. (author)

Modification of conventional X-ray diffractometer for the measurement of phase distribution in a narrow region

Energy Technology Data Exchange (ETDEWEB)

Park, Yang-Soon; Han, Sun-Ho; Kim, Jong-Goo; Jee, Kwang-Yong; Kim, Won-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2006-10-15

An X-ray diffractometer for spatially resolved X-ray diffraction measurements was developed to identify phase in the narrow (micron-scaled) region of high burn-up fuels and some nuclear materials. The micro-SRD was composed of an X-ray microbeam alignment system and a sample micro translation system instead of a normal slit and a fixed sample stage in a commercial XRD. The X-ray microbeam alignment system was fabricated with a microbeam concentrator having two Ni deposited mirrors, a vertical positioner, and a tilt table for the generation of a concentrated microbeam. The sample micro translation system was made with a sample holder and a horizontal translator, allowing movement of a specimen at 5 {mu}m steps. The angular intensity profile of the microbeam generated through a concentrator was symmetric and not distorted. The size of the microbeam was 4,000 x 20{mu}m and the spatial resolution of the beam was 47 {mu}m at the sample position. When the diffraction peaks were measured for a UO{sub 2} pellet specimen by this system, the reproducibility (2{theta} = {+-}0.01 .deg.) of the peaks was as good as a conventional X-ray diffractometer. For the cross section of oxidized titanium metal, not only TiO{sub 2} in an outer layer but also TiO near an oxide-metal interface was observed.

X-ray sources associated with young stellar objects in the star formation region CMa R1

Science.gov (United States)

Santos-Silva, Thais; Gregorio-Hetem, Jane; Montmerle, Thierry

2013-07-01

In previous works we studied the star formation scenario in the molecular cloud Canis Major R1 (CMa R1), derived from the existence of young stellar population groups near the Be stars Z CMa and GU CMa. Using data from the ROSAT X-ray satellite, having a field-of-view of ~ 1° in diameter, Gregorio-Hetem et al. (2009) discovered in this region young stellar objects mainly grouped in two clusters of different ages, with others located in between. In order to investigate the nature of these objects and to test a possible scenario of sequential star formation in this region, four fields (each 30 arcmin diameter, with some overlap) have been observed with the XMM-Newton satellite, with a sensitivity about 10 times better than ROSAT. The XMM-Newton data are currently under analysis. Preliminary results indicate the presence of about 324 sources, most of them apparently having one or more near-infrared counterparts showing typical colors of young stars. The youth of the X-ray sources was also confirmed by X-ray hardness ratio diagrams (XHRD), in different energy bands, giving an estimate of their Lx/Lbol ratios. In addition to these results, we present a detailed study of the XMM field covering the cluster near Z CMa. Several of these sources were classified as T Tauri and Herbig Ae/Be stars, using optical spectroscopy obtained with Gemini telescopes, in order to validate the use of XHRD applied to the entire sample. This classification is also used to confirm the relation between the luminosities in the near-infrared and X-ray bands expected for the T Tauri stars in CMa R1. In the present work we show the results of the study based on the spectra of about 90 sources found nearby Z CMa. We checked that the X-ray spectra (0.3 to 10 keV) of young objects is different from that observed in field stars and extragalactic objects. Some of the candidates also have light curve showing flares that are typical of T Tauri stars, which confirms the young nature of these X

Small x physics

International Nuclear Information System (INIS)

Kwiecinski, J.

1993-01-01

The QCD expectations concerning the small x limit of parton distributions where x is the Bjorken scaling variable are reviewed. This includes discussion of the evolutions equations in the small x region, the Lipatov equation which sums the leading powers of ln(1/x) and the shadowing effects. Phenomenological implantations of the theoretical expectations for the deep inelastic lepton-hadron scattering in the small x region which will be accessible at the HERA ep collider are described. We give predictions for structure functions F 2 and F L and discuss specific processes sensitive to the small x physics such as heavy quark production, deep inelastic diffraction and jet production in deep inelastic lepton scattering. A brief review of nuclear shadowing in the inelastic lepton nucleus scattering at small x is also presented. (author). 86 refs, 29 figs

Comparison of photospheric electric current and ultraviolet and x-ray emission in a solar active region

International Nuclear Information System (INIS)

Haisch, B.M.; Bruner, M.E.; Hagyard, M.J.; Bonnet, R.M.; NASA, Marshall Space Flight Center, Huntsville, AL; ESA, Paris, France)

1986-01-01

This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft x-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region. 29 references

Molecular markers for X-ray-insensitive differentiated cells in the Inner and outer regions of the mesenchymal space in planarian Dugesia japonica.

Science.gov (United States)

Teramoto, Machiko; Kudome-Takamatsu, Tomomi; Nishimura, Osamu; An, Yang; Kashima, Makoto; Shibata, Norito; Agata, Kiyokazu

2016-09-01

Planarian's strong regenerative ability is dependent on stem cells (called neoblasts) that are X-ray-sensitive and proliferative stem cells. In addition to neoblasts, another type of X-ray-sensitive cells was newly identified by recent research. Thus, planarian's X-ray-sensitive cells can be divided into at least two populations, Type 1 and Type 2, the latter corresponding to planarian's classically defined "neoblasts". Here, we show that Type 1 cells were distributed in the outer region (OR) immediately underneath the muscle layer at all axial levels from head to tail, while the Type 2 cells were distributed in a more internal region (IR) of the mesenchymal space at the axial levels from neck to tail. To elucidate the biological significance of these two regions, we searched for genes expressed in differentiated cells that were locate close to these X-ray-sensitive cell populations in the mesenchymal space, and identified six genes mainly expressed in the OR or IR, named OR1, OR2, OR3, IR1, IR2 and IR3. The predicted amino acid sequences of these genes suggested that differentiated cells expressing OR1, OR3, IR1, or IR2 provide Type 1 and Type 2 cells with specific extracellular matrix (ECM) environments. © 2016 Japanese Society of Developmental Biologists.

Analysis and interpretation of soft X-ray photographs of coronal active regions taken with Fresnel zone plates. I

International Nuclear Information System (INIS)

Kraemer, G.; Einighammer, H.J.; Elwert, G.; Braeuninger, H.; Fink, H.H.; Truemper, J.

1978-01-01

Soft X-ray photographs of the Sun taken at O VII 21.6 A and in a spectral band ranging from 13.2 to 22.1 A have been analysed in order to establish spatially resolved maps of temperature and emission measure for several active regions in the corona. The photographs were taken on 11 March, 1971, and on 2 March, 1972, with Fresnel zone plate cameras which were flown on ESRO and NRI sounding rockets. The authors deal with those aspects of the instrumentation which are important for setting up a suitable image analysis procedure. The characteristics of the wavelength dependent image formation by zone plates combined with absorption filters are discussed. Results of the calibration of the X-ray film are given. Then a specific iterative data reduction procedure is described and finally the resulting maps of temperature and emission measure are presented for a selected active region. (Auth.)

High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images.

Science.gov (United States)

Leong, Andrew F T; Fouras, Andreas; Islam, M Sirajul; Wallace, Megan J; Hooper, Stuart B; Kitchen, Marcus J

2013-04-01

Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions ≈ 16.2 μm). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using this technique, it is possible to measure

Hearing Impaired Education of the Department of Education in Region X, Philippines: Its Approaches and Implication

Directory of Open Access Journals (Sweden)

James Mirabeau B. Undalok

2015-11-01

Full Text Available One way to attain improvement of the educational programs of the hearing impaired is by conducting survey and assessment of the status of the hearing impaired education of the Department of Education in Region X, Philippines. The Special Education (SpEd teachers play a vital role for the pupils of the hearing impaired children as they are viewed as linchpins in the learning process of the children. This cannot be attained without the different approaches on hearing impaired education. Survey -questionnaires were used to gather information needed. Data were analyzed using the descriptive statistics such as weighted mean and standard deviation. The ANOVA test was used to determine the significance of the hearing impaired education of the Department of Education in Region X. Anchored on the findings, the following conclusions are made about different educational approaches should be given priority by the SPED teachers is further enhance the lifelong learning skills of the pupils. It helps them for their learning process and acquiring language skills. There should be an advocacy on the hearing impaired education program to the public and stakeholders.

Regional and local land subsidence at the Venice coastland by TerraSAR-X PSI

Directory of Open Access Journals (Sweden)

L. Tosi

2015-11-01

Full Text Available Land subsidence occurred at the Venice coastland over the 2008–2011 period has been investigated by Persistent Scatterer Interferometry (PSI using a stack of 90 TerraSAR-X stripmap images with a 3 m resolution and a 11-day revisiting time. The regular X-band SAR acquisitions over more than three years coupled with the very-high image resolution has significantly improved the monitoring of ground displacements at regional and local scales, e.g., the entire lagoon, especially the historical palaces, the MoSE large structures under construction at the lagoon inlets to disconnect the lagoon from the Adriatic Sea during high tides, and single small structures scattered within the lagoon environments. Our results show that subsidence is characterized by a certain variability at the regional scale with superimposed important local displacements. The movements range from a gentle uplift to subsidence rates of up to 35 mm yr−1. For instance, settlements of 30–35 mm yr−1 have been detected at the three lagoon inlets in correspondence of the MoSE works, and local sinking bowls up to 10 mm yr−1 connected with the construction of new large buildings or restoration works have been measured in the Venice and Chioggia historical centers. Focusing on the city of Venice, the mean subsidence of 1.1 ± 1.0 mm yr−1 confirms the general stability of the historical center.

X-ray chest mass screening for pulmonary tuberculosis in Friuli Venezia Giulia region, Italy

International Nuclear Information System (INIS)

Barbina, V.; Contento, G.; Padovani, R.; Pitzalis, G.; Nigris, C.

1987-01-01

Since 1980, the law which instituted the National Health Service (NHS) in Italy, attributing both the organization and the administration of all public health services to local government bodies referred to as 'Regioni', is being gradually enforced. One result is that the mass screening services are now set up on local basis, involving important practice and regulatory changes. These in particular concern chest X-ray mass screening centers, which were formerly organized as Provincial Antituberculosis Services, supervised by the Ministry of Health and dealing almost exclusively with pulmonary tuberculosis (PTB). Today, chest X-ray mass screening is carried on the 'Centri Sociali di Pneumologia', which in some case inherited the staff and diagnostic facilities of Provincial Antituberculosis Services, but are directed by the Councillorship of Health of the 'Regioni' and, in most cases, deal with the diagnosis and care of general pulmonary diseases. Therefore, regulations and practices of mass screening are eventually different in most Italian 'Regioni', depending on different economic and social situations. In this connection, this paper reports up-to-date information and data on frequency, effectiveness, cost and radiation risks of chest X-ray screening in the 'Regione Autonoma Friuli Venezia Giulia' (FVG), North-East Italy, population 1,300,000

Microstructures and coherent phase diagram for the pseudobinary system (AuCu)1-xPd x with x ≤ 0.10

International Nuclear Information System (INIS)

Luciano, Rhodora H.; Shiraishi, Takanobu; Udoh, Koh-ichi; Tanaka, Yasuhiro; Hisatsune, Kunihiro

2005-01-01

A coherent phase diagram for the pseudobinary system (AuCu) 1-x Pd x with x ≤ 0.10 was constructed based on phase identification and microstructural analysis by transmission electron microscopy. It was confirmed that the addition of palladium exceeding 1.0 at.% to the equiatomic AuCu eliminated the AuCu II long-period superstructure from the phase equilibria and stabilized the AuCu I superstructure. The AuCu-0.5 at.% Pd and AuCu-1.0 at.% Pd alloys isothermally aged for long time at temperatures ranging from 380 to 420 deg. C exhibited seven distinguishable regions; a single-phase region of disordered solid solution (α); a single-phase region of AuCu I ordered phase; a single-phase region of AuCu II ordered phase; a region of the coexisting AuCu I and AuCu II ordered phases; a region of the coexisting AuCu I ordered and α phases; a region of the coexisting AuCu II ordered and α phases; and a region of the coexisting AuCu I and AuCu II ordered and α phases

Redetermination of the X-ray spectrum of SN 1006 and excess diffuse emission from the Lupus region

Energy Technology Data Exchange (ETDEWEB)

Koyama, Katsuji; Tsunemi, Hiroshi; Becker, R H; Hughes, J P

1987-01-01

X-ray from SN 1006 and from the adjacent Lupus region were separately observed with the Tenma gas scintillation proportional counters. The spectrum of the local excess emission from the Lupus region can be consistently fitted with either a thin thermal bremsstrahlung spectrum with a temperature of 7.5 +- 2.6 keV or a power-law spectrum with a photon index of 2.1 +- 0.1. The x-ray emission from SN 1006, after subtraction of this local excess, has a spectrum which can be described as a power-law spectrum with a photon index of 3.3 +- 0.1 or a thin thermal bremsstrahlung spectrum with a temperature of 1.9 +- 0.1 keV which is much softer than the previously reported spectrum. No significant iron line emission was observed in the SN 1006 spectrum. The 90 % upper limit for the equivalent width of the iron line was reduced to 400 eV. The observed spectrum can also be interpreted in terms of a nonequilibrium ionization model of about 2-keV electron temperature.

X ray spectra of X Per. [oso-8 observations

Science.gov (United States)

Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

1978-01-01

The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

Charge-carrier dynamics in polycrystalline thin-film CuIn{sub 1−x}Ga{sub x}Se{sub 2} photovoltaic devices after pulsed laser excitation: Interface and space-charge region analysis

Energy Technology Data Exchange (ETDEWEB)

Kuciauskas, Darius; Li, Jian V.; Kanevce, Ana; Guthrey, Harvey; Contreras, Miguel; Pankow, Joel; Dippo, Pat; Ramanathan, Kannan [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401-3305 (United States)

2015-05-14

We used time-resolved photoluminescence (TRPL) spectroscopy to analyze time-domain and spectral-domain charge-carrier dynamics in CuIn{sub 1−x}Ga{sub x}Se{sub 2} (CIGS) photovoltaic (PV) devices. This new approach allowed detailed characterization for the CIGS/CdS buffer interface and for the space-charge region. We find that dynamics at the interface is dominated by diffusion, where the diffusion rate is several times greater than the thermionic emission or interface recombination rate. In the space-charge region, the electric field of the pn junction has the largest effect on the carrier dynamics. Based on the minority-carrier (electron) drift-rate dependence on the electric field strength, we estimated drift mobility in compensated CuIn{sub 1−x}Ga{sub x}Se{sub 2} (with x ≈ 0.3) as 22 ± 2 cm{sup 2}(Vs){sup −1}. Analysis developed in this study could be applied to evaluate interface and junction properties of PV and other electronic devices. For CIGS PV devices, TRPL spectroscopy could contribute to understanding effects due to absorber compositional grading, which is one of the focus areas in developing record-efficiency CIGS solar cells.

A two component model describing nucleon structure functions in the low-x region

Energy Technology Data Exchange (ETDEWEB)

Bugaev, E.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 7a, 60th October Anniversary prospect, Moscow 117312 (Russian Federation); Mangazeev, B.V. [Irkutsk State University, 1, Karl Marx Street, Irkutsk 664003 (Russian Federation)

2009-12-15

A two component model describing the electromagnetic nucleon structure functions in the low-x region, based on generalized vector dominance and color dipole approaches is briefly described. The model operates with the mesons of rho-family having the mass spectrum of the form m{sub n}{sup 2}=m{sub r}ho{sup 2}(1+2n) and takes into account the nondiagonal transitions in meson-nucleon scattering. The special cut-off factors are introduced in the model, to exclude the gamma-qq-bar-V transitions in the case of narrow qq-bar-pairs. For the color dipole part of the model the well known FKS-parameterization is used.

A comparison of photospheric electric current and ultraviolet and X-ray emission in a solar active region

Science.gov (United States)

Haisch, B. M.; Bruner, M. E.; Hagyard, M. J.; Bonnet, R. M.

1986-01-01

This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft X-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region.

[The property and applications of the photovoltaic solar panel in the region of diagnostic X-ray].

Science.gov (United States)

Hirota, Jun'ichi; Tarusawa, Kohetsu; Kudo, Kohsei

2010-10-20

In this study, the sensitivity in the diagnostic X-ray region of the single crystalline Si photovoltaic solar panel, which is expected to grow further, was measured by using an X-ray tube. The output voltage of the solar panel was clearly proportional to the tube voltage and a good time response in the irradiation time setting of the tube was measured. The factor which converts measured voltage to irradiation dose was extracted experimentally using a correction filter to investigate the ability of the solar panel as a dose monitor. The obtained conversion factors were N(S) = 13 ± 1[µV/µSv/s] for the serial and N(P) = 58 ± 2[µV/µSv/s] for the parallel connected solar panels, both with the Al 1 mm + Cu 0.1 mm correction filter, respectively. Therefore, a good dose dependence of the conversion factor was confirmed by varying the distance between the X-ray tube and the solar panel with that filter. In conclusion, a simple extension of our results pointed out the potential of a new concept of measurements using, for example, the photovoltaic solar panel, the direct dose measurement from X-ray tube and real time estimation of the exposed dose in IVR.

Anisotropy of the penetration depth in La2-xSrxCuO4 in underdoped and overdoped regions

Science.gov (United States)

Zaleski, A. J.; Klamut, J.

1999-12-01

We present the results of measurements of the penetration depth anisotropy in pulverized, ceramic La2-xSrxCuO4. The measurements were carried out for x = 0.08, 0.1, 0.125, 0.15 and 0.2. The powdered samples, immersed in wax, were magnetically oriented in a static magnetic field of 10 T. The penetration depth in the a-b plane, icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/>ab, and perpendicular to it, icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/>icons/Journals/Common/perp" ALT="perp" ALIGN="MIDDLE"/>, were derived from alternating-current susceptibility measurements. For underdoped samples they both vary linearly with temperature (for the low-temperature region), while for the samples from the overdoped region the measured points can be fitted by an exponential function. These results support Uemura's picture (Uemura Y J 1997 Physica C 282-287 194) of crossover from Bose-Einstein condensation to a Bardeen-Cooper-Schrieffer mechanism of superconductivity. The penetration depth values extrapolated to T = 0 may be described by a quadratic function of the strontium concentration (for both icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/>ab and icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/>icons/Journals/Common/perp" ALT="perp" ALIGN="MIDDLE"/>). The anisotropy of the penetration depth as a function of the substitution shows a similar dependence to the critical temperature Tc(x).

Neutron scattering investigations of the properties of the x - T phase diagram of Rb sub 1 sub - sub x (NH sub 4) sub x I mixed crystals

CERN Document Server

Smirnov, L S; Savenko, B N

2002-01-01

The x - T phase diagram of Rb sub 1 sub - sub x (NH sub 4) sub x I is studied using samples with the ammonium concentration 0.01<x<0.77 over a wide temperature region of 15 to 300 K by neutron powder diffraction and inelastic incoherent neutron scattering. The results of powder diffraction studies show that at low temperatures a phase transition from alpha-phase to beta-phase is observed at ammonium concentrations x = 0.50 and x = 0.66. Inelastic incoherent neutron scattering detects a region of the orientional glass state at ammonium concentrations 0.29<x,0.40

Synaptonemal complex aberrations in the pseudoautosomal region of X, Y chromosomes in irradiated hamsters

Energy Technology Data Exchange (ETDEWEB)

Allen, J.W.; Collins, B.W. [Environmental Protection Agency, Research Triangle Park, NC (United States); Poorman-Allen, P. [Wellcome Research Lab., Research Triangle Park, N.C. (United States); Sontag, M.R. [Duke Univ., Durham, NC (United States). Medical Center

1994-05-01

The effects of X-radiation, bleomycin and amsacrine (m-AMSA) on the meiotic chromosomes of male Armenian hamsters were determined by electron microscopic analysis of synaptonemal complex (SC) damage. Pachytene stage cells were analyzed 5 or 6 days following their treatment at putative preleptotene-leptotene stages of meiosis. Of the multiple types of SC aberrations observed to be significantly increased over control levels, lateral element breakage and synaptic anomalies were most prevalent. The focus of these studies was on the sex chromosomes which, in the Armenian hamster, reveal an unusally well-defined pseudoautosomal region. In the XY pair, radiation and chemical treatments caused certain forms of structural and synaptic anomalies which appeared to be preferentially localized to telomeric and/or crossover regions. The nature of these specific aberrations, involving breakage, bridge formation and asynapsis, is not well understood; however, their distributions are suggestive of possible relationships with sites and processes of crossing over. (author).

Incompatibility between X chromosome factor and pericentric heterochromatic region causes lethality in hybrids between Drosophila melanogaster and its sibling species.

Science.gov (United States)

Cattani, M Victoria; Presgraves, Daven C

2012-06-01

The Dobzhansky-Muller model posits that postzygotic reproductive isolation results from the evolution of incompatible epistatic interactions between species: alleles that function in the genetic background of one species can cause sterility or lethality in the genetic background of another species. Progress in identifying and characterizing factors involved in postzygotic isolation in Drosophila has remained slow, mainly because Drosophila melanogaster, with all of its genetic tools, forms dead or sterile hybrids when crossed to its sister species, D. simulans, D. sechellia, and D. mauritiana. To circumvent this problem, we used chromosome deletions and duplications from D. melanogaster to map two hybrid incompatibility loci in F(1) hybrids with its sister species. We mapped a recessive factor to the pericentromeric heterochromatin of the X chromosome in D. simulans and D. mauritiana, which we call heterochromatin hybrid lethal (hhl), which causes lethality in F(1) hybrid females with D. melanogaster. As F(1) hybrid males hemizygous for a D. mauritiana (or D. simulans) X chromosome are viable, the lethality of deficiency hybrid females implies that a dominant incompatible partner locus exists on the D. melanogaster X. Using small segments of the D. melanogaster X chromosome duplicated onto the Y chromosome, we mapped a dominant factor that causes hybrid lethality to a small 24-gene region of the D. melanogaster X. We provide evidence suggesting that it interacts with hhl(mau). The location of hhl is consistent with the emerging theme that hybrid incompatibilities in Drosophila involve heterochromatic regions and factors that interact with the heterochromatin.

Comparison of x-ray output of inverter-type x-ray equipment

International Nuclear Information System (INIS)

Asano, Hiroshi; Miyake, Hiroyuki; Yamamoto, Keiichi

2000-01-01

The x-ray output of 54 inverter-type x-ray apparatuses used at 18 institutions was investigated. The reproducibility and linearity of x-ray output and variations among the x-ray equipment were evaluated using the same fluorescence meter. In addition, the x-ray apparatuses were re-measured using the same non-invasive instrument to check for variations in tube voltage, tube current, and irradiation time. The non-invasive instrument was calibrated by simultaneously obtaining measurements with an invasive instrument, employing the tube voltage and current used for the invasive instrument, and the difference was calculated. Reproducibility of x-ray output was satisfactory for all x-ray apparatuses. The coefficient of variation was 0.04 or less for irradiation times of 5 ms or longer. In 84.3% of all x-ray equipment, variation in the linearity of x-ray output was 15% or less for an irradiation time of 5 ms. However, for all the apparatuses, the figure was 50% when irradiation time was the shortest (1 to 3 ms). Variation in x-ray output increased as irradiation time decreased. Variation in x-ray output ranged between 1.8 and 2.5 compared with the maximum and minimum values, excluding those obtained at the shortest irradiation time. The relative standard deviation ranged from ±15.5% to ±21.0%. The largest variation in x-ray output was confirmed in regions irradiated for the shortest time, with smaller variations observed for longer irradiation times. The major factor responsible for variation in x-ray output in regions irradiated for 10 ms or longer, which is a relatively long irradiation time, was variation in tube current. Variation in tube current was slightly greater than 30% at maximum, with an average value of 7% compared with the preset tube current. Variations in x-ray output in regions irradiated for the shortest time were due to photographic effects related to the rise and fall times of the tube voltage waveform. Accordingly, in order to obtain constant x

A redetermination of the X-ray spectrum of SN 1006 and excess diffuse emission from the Lupus region

International Nuclear Information System (INIS)

Koyama, Katsuji; Tsunemi, Hiroshi; Becker, R.H.; Hughes, J.P.

1987-01-01

X-ray from SN 1006 and from the adjacent Lupus region were separately observed with the Tenma gas scintillation proportional counters. The spectrum of the local excess emission from the Lupus region can be consistently fitted with either a thin thermal bremsstrahlung spectrum with a temperature of 7.5 ± 2.6 keV or a power-law spectrum with a photon index of 2.1 ± 0.1. The x-ray emission from SN 1006, after subtraction of this local excess, has a spectrum which can be described as a power-law spectrum with a photon index of 3.3 ± 0.1 or a thin thermal bremsstrahlung spectrum with a temperature of 1.9 ± 0.1 keV which is much softer than the previously reported spectrum. No significant iron line emission was observed in the SN 1006 spectrum. The 90 % upper limit for the equivalent width of the iron line was reduced to 400 eV. The observed spectrum can also be interpreted in terms of a nonequilibrium ionization model of about 2-keV electron temperature. (author)

Study of substitution in the systems UNi5sub(-)sub(x)Msub(x) and ZrNi5sub(-)sub(x)Msub(x) (M = In, Sn, Zn)

International Nuclear Information System (INIS)

Blazina, Z.; Drasner, A.; Ban, Z.; Zagreb Univ.

1981-01-01

X-ray powder diffraction studies and metallographic examinations in the systems UNi 5 sub(-)sub(x)Msub(x) and ZrNi 5 sub(-)sub(x)Msub(x) (M = In, Sn, Zn) revealed the existence of single phase regions up to the composition 1 : 4 : 1, i.e. up to UNi 4 M and ZrNi 4 M, respectively. Comparison between calculated and observed intensity values showed that nickel atoms, in the crystallographic positions 4(c) of the isostructural binary compounds UNi 5 or ZrNi 5 (UNi 5 -type, S.G. F43m), are substituted by M atoms. Vegard's rule is obeyed in the single phase regions of all investigated systems. The crystal structures of UNi 4 M and ZrNi 4 M are superlattice structures of the MgSnCu 4 -type (S.G. F43m). Structural correlations of these phases with corresponding binary prototypes are made in terms of stacking sequences. (orig.)

Photoluminescence of Eu2+-doped CaMgSi2xO6+2x (1.00≤x≤1.20) phosphors in UV-VUV region

International Nuclear Information System (INIS)

Zhang Zhiya; Wang Yuhua

2008-01-01

Alkaline-earth silicate phosphors CaMgSi 2x O 6+2x :Eu 2+ (1.00≤x≤1.20) were prepared by traditional solid-state reaction. The phosphors showed an intense blue emission centered around 453 nm, with both 254 and 147 nm excitations. The host absorption below 200 nm in the excitation spectra consisted of two bands around 160 and 190 nm. The band around 160 nm was ascertained to be associated with the SiO 4 -tetrahedra and MgO 6 -polyhedra, and that around 190 nm was due to the CaO 8 -polyhedra or some impurities. The incorporation of excess Si of less than 15% would not lead to formation of impurities and the results indicated that an appropriate Si excess could improve the Photoluminescence (PL) intensity in both ultraviolet (UV) and vacuum ultraviolet (VUV) regions

Mutations in noncoding regions of GJB1 are a major cause of X-linked CMT

Science.gov (United States)

Tomaselli, Pedro J.; Rossor, Alexander M.; Horga, Alejandro; Jaunmuktane, Zane; Carr, Aisling; Saveri, Paola; Piscosquito, Giuseppe; Pareyson, Davide; Laura, Matilde; Blake, Julian C.; Poh, Roy; Polke, James; Houlden, Henry

2017-01-01

Objective: To determine the prevalence and clinical and genetic characteristics of patients with X-linked Charcot-Marie-Tooth disease (CMT) due to mutations in noncoding regions of the gap junction β-1 gene (GJB1). Methods: Mutations were identified by bidirectional Sanger sequence analysis of the 595 bases of the upstream promoter region, and 25 bases of the 3′ untranslated region (UTR) sequence in patients in whom mutations in the coding region had been excluded. Clinical and neurophysiologic data were retrospectively collected. Results: Five mutations were detected in 25 individuals from 10 kindreds representing 11.4% of all cases of CMTX1 diagnosed in our neurogenetics laboratory between 1996 and 2016. Four pathogenic mutations, c.-17G>A, c.-17+1G>T, c.-103C>T, and c.-146-90_146-89insT were detected in the 5′UTR. A novel mutation, c.*15C>T, was detected in the 3′ UTR of GJB1 in 2 unrelated families with CMTX1 and is the first pathogenic mutation in the 3′UTR of any myelin-associated CMT gene. Mutations segregated with the phenotype, were at sites predicted to be pathogenic, and were not present in the normal population. Conclusions: Mutations in noncoding DNA are a major cause of CMTX1 and highlight the importance of mutations in noncoding DNA in human disease. Next-generation sequencing platforms for use in inherited neuropathy should therefore include coverage of these regions. PMID:28283593

Detection of Chromosome X;18 Breakpoints and Translocation of the Xq22.3;18q23 Regions Resulting in Variable Fertility Phenotypes

Directory of Open Access Journals (Sweden)

Attila Szvetko

2012-01-01

Full Text Available We describe a familial pattern of gonosomal-autosomal translocation between the X and 18 chromosomes, balanced and unbalanced forms, in male and female siblings. The proposita was consulted for hypergonadotropic hypogonadism. Karyotype analysis revealed a balanced 46, X, t(X;18(q22.3;q23 genotype. The sister of the proband presented with oligomenorrhea with irregular menses and possesses an unbalanced form of the translocation 46, X, der(X, t(X;18(q22.3;q23. The brother of the proband was investigated and was found to possess the balanced form of the same translocation, resulting in disrupted spermatogenesis. Maternal investigation revealed the progenitor karyotype 46, X, t(X;18(q22.3;q23. Maternal inheritance and various genomic events contributed to the resultant genotypes. Primary infertility was initially diagnosed in all progeny; however, the male individual recently fathered twins. We briefly review the mechanisms associated with X;18 translocations and describe a pattern of inheritance, where breakpoints and translocation of the Xq22.3;18q23 regions have resulted in variable fertility.

The REgolith X-Ray Imaging Spectrometer (REXIS) for OSIRIS-REx: identifying regional elemental enrichment on asteroids

Science.gov (United States)

Allen, Branden; Grindlay, Jonathan; Hong, Jaesub; Binzel, Richard P.; Masterson, Rebecca; Inamdar, Niraj K.; Chodas, Mark; Smith, Matthew W.; Bautz, Marshall W.; Kissel, Steven E.; Villasenor, Joel; Oprescu, Miruna; Induni, Nicholas

2013-09-01

The OSIRIS-REx Mission was selected under the NASA New Frontiers program and is scheduled for launch in September of 2016 for a rendezvous with, and collection of a sample from the surface of asteroid Bennu in 2019. 101955 Bennu (previously 1999 RQ36) is an Apollo (near-Earth) asteroid originally discovered by the LINEAR project in 1999 which has since been classified as a potentially hazardous near-Earth object. The REgolith X-Ray Imaging Spectrometer (REXIS) was proposed jointly by MIT and Harvard and was subsequently accepted as a student led instrument for the determination of the elemental composition of the asteroid's surface as well as the surface distribution of select elements through solar induced X-ray fluorescence. REXIS consists of a detector plane that contains 4 X-ray CCDs integrated into a wide field coded aperture telescope with a focal length of 20 em for the detection of regions with enhanced abundance in key elements at 50 m scales. Elemental surface distributions of approximately 50-200 m scales can be detected using the instrument as a simple collimator. An overview of the observation strategy of the REXIS instrument and expected performance are presented here.

Structure functions at low x

International Nuclear Information System (INIS)

Roeck, A.De.

2000-01-01

Deep recent data and phenomenology on low-x structure functions are discussed inelastic scattering. We will be interested primordially in the regions Q 2 → 0 i.e. the transition from γp to, and x → 10 -4 - 10 -6 i.e. the region of high parton densities

Low x Double ln2(1/x) Resummation Effects at the Sum Rules for Nucleon Structure Function g1

International Nuclear Information System (INIS)

Ziaja, B.

2001-01-01

We have estimated the contributions to the moments of polarized nucleon structure function g 1 (x,Q 2 ) coming from the region of the very low x (10 -5 2 (1/x) resummation. The Q 2 evolution of g 1 was described by the unified evolution equations incorporating both the leading order Altarelli-Parisi evolution at large and moderate x, and the double ln 2 (1/x) resummation at small x. The moments were obtained by integrating out the extrapolated nucleon structure function in the region 10 -5 < x<1. (author)

Modeling active region transient brightenings observed with X-ray telescope as multi-stranded loops

Energy Technology Data Exchange (ETDEWEB)

Kobelski, Adam R.; McKenzie, David E. [Department of Physics, P.O. Box 173840, Montana State University, Bozeman, MT 59717-3840 (United States); Donachie, Martin, E-mail: kobelski@solar.physics.montana.edu [University of Glasgow, Glasgow, G128QQ, Scotland (United Kingdom)

2014-05-10

Strong evidence exists that coronal loops as observed in extreme ultraviolet and soft X-rays may not be monolithic isotropic structures, but can often be more accurately modeled as bundles of independent strands. Modeling the observed active region transient brightenings (ARTBs) within this framework allows for the exploration of the energetic ramifications and characteristics of these stratified structures. Here we present a simple method of detecting and modeling ARTBs observed with the Hinode X-Ray Telescope (XRT) as groups of zero-dimensional strands, which allows us to probe parameter space to better understand the spatial and temporal dependence of strand heating in impulsively heated loops. This partially automated method can be used to analyze a large number of observations to gain a statistical insight into the parameters of coronal structures, including the number of heating events required in a given model to fit the observations. In this article, we present the methodology and demonstrate its use in detecting and modeling ARTBs in a sample data set from Hinode/XRT. These initial results show that, in general, multiple heating events are necessary to reproduce observed ARTBs, but the spatial dependence of these heating events cannot yet be established.

Modeling active region transient brightenings observed with X-ray telescope as multi-stranded loops

International Nuclear Information System (INIS)

Kobelski, Adam R.; McKenzie, David E.; Donachie, Martin

2014-01-01

Strong evidence exists that coronal loops as observed in extreme ultraviolet and soft X-rays may not be monolithic isotropic structures, but can often be more accurately modeled as bundles of independent strands. Modeling the observed active region transient brightenings (ARTBs) within this framework allows for the exploration of the energetic ramifications and characteristics of these stratified structures. Here we present a simple method of detecting and modeling ARTBs observed with the Hinode X-Ray Telescope (XRT) as groups of zero-dimensional strands, which allows us to probe parameter space to better understand the spatial and temporal dependence of strand heating in impulsively heated loops. This partially automated method can be used to analyze a large number of observations to gain a statistical insight into the parameters of coronal structures, including the number of heating events required in a given model to fit the observations. In this article, we present the methodology and demonstrate its use in detecting and modeling ARTBs in a sample data set from Hinode/XRT. These initial results show that, in general, multiple heating events are necessary to reproduce observed ARTBs, but the spatial dependence of these heating events cannot yet be established.

An electron storage ring as primary standard for the realization of radiation optical units from the infrared to the soft X-ray region

International Nuclear Information System (INIS)

Riehle, F.; Wende, B.

1987-01-01

The electron storage ring BESSY optimized for radiometry is shown to be a primary standard of spectral photon flux with a relative uncertainty increasing from 0.3% in the infrared (photon energy ≅ 1 eV) to 2% in the soft X-ray region (photon energy ≅ 5 keV). The small uncertainties at high photon energies were achieved by measuring the spatial and angular distributions of the electrons around the mean electron orbit and by calculating the corresponding distributions of the emitted synchrotron radiation. Results of various intercomparisons with other standards in the near infrared, visible, and soft X-ray region support the low uncertainties of this new primary standard. (orig.)

Presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution: A Rietveld study

Energy Technology Data Exchange (ETDEWEB)

Pandey, Rishikesh, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2014-07-28

We present here the results of structural studies on multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution using Rietveld analysis on powder x-ray diffraction data in the composition range 0.35 ≤ x ≤ 0.55. The stability region of various crystallographic phases at room temperature for (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} is determined precisely. Structural transformation from pseudo-cubic (x ≤ 0.40) to tetragonal (x ≥ 0.50) phase is observed via phase coexistence region demarcating the morphotropic phase boundary. The morphotropic phase boundary region consists of coexisting tetragonal and monoclinic structures with space group P4mm and Pm, respectively, stable in composition range 0.41 ≤ x ≤ 0.49 as confirmed by Rietveld analysis. The results of Rietveld analysis completely rule out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier workers. A comparison between the bond lengths for “B-site cations-oxygen anions” obtained after Rietveld refinement, with the bond length calculated using Shannon-Prewitt ionic radii, reveals the ionic nature of B-O (Ni/Ti-O) bonds for the cubic phase and partial covalent character for the other crystallographic phases.

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

Energy Technology Data Exchange (ETDEWEB)

Takagi, H., E-mail: takagih@post.kek.jp; Igarashi, N.; Mori, T.; Saijo, S.; Nagatani, Y.; Shimizu, N. [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Ohta, H. [Mitsubishi Electric System & Service Co., Ltd, Accelerator Engineering Center, 2-8- 8 Umezono, Tsukuba, Ibaraki 305-0045 (Japan); Yamamoto, K. [Graduate School of Engineering, Department of Materials Science & Technology, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

2016-10-14

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers and can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q{sub z} direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

International Nuclear Information System (INIS)

Takagi, H.; Igarashi, N.; Mori, T.; Saijo, S.; Nagatani, Y.; Shimizu, N.; Ohta, H.; Yamamoto, K.

2016-01-01

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers and can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q_z direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.

X-ray photographs of a solar active region with a multilayer telescope at normal incidence

Science.gov (United States)

Underwood, J. H.; Bruner, M. E.; Haisch, B. M.; Brown, W. A.; Acton, L. W.

1987-01-01

An astronomical photograph was obtained with a multilayer X-ray telescope. A 4-cm tungsten-carbon multilayer mirror was flown as part of an experimental solar rocket payload, and successful images were taken of the sun at normal incidence at a wavelength of 44 A. Coronal Si XII emission from an active region was recorded on film; as expected, the structure is very similar to that observed at O VIII wavelengths by the Solar Maximum Mission flat-crystal spectrometer at the same time. The small, simple optical system used in this experiment appears to have achieved a resolution of 5 to 10 arcsec.

Detailed ordering of markers localizing to the Xq26-Xqter region of the human X chromosome by the use of an interspecific Mus spretus mouse cross

International Nuclear Information System (INIS)

Avner, P.; Amar, L.; Arnaud, D.; Hanauer, A.; Cambrou, J.

1987-01-01

Five probes localizing to the Xq26-Xqter region of the human X chromosome have been genetically mapped on the mouse X chromosome using an interspecific cross involving Mus spretus to a contiguous region lying proximally to the Tabby (Ta) locus. Pedigree and recombinational analysis establish the marker order as being Hprt-FIX-c11-G6PD-St14-1. The size of this contiguous region is such that the X-linked muscular dystrophy (mdx) mouse mutation probably maps within this segment. This in turn suggests that it is highly improbable that the mouse mdx locus represents a model for Duchenne muscular dystrophy (DMD). It is, however, compatible with the idea that this mutation may correspond in man to Emery Dreifuss muscular dystrophy. The high frequency of restriction fragment length polymorphisms found in this interspecific system for all the human cross-reacting probes examined up until now, using only a limited number of restriction enzymes, suggests that the Mus spretus mapping system may be of great potential value for establishing the linkage relationships existing in man when conserved chromosomal regions are concerned and human/mouse cross-reacting probes are available or can be obtained

Correlation between the pionization region and the fragmentation region in high energy proton-proton collisions

CERN Document Server

Albrow, M G; Barber, D P; Bogaerts, A; Bosnjakovic, B; Brooks, J R; Clegg, A B; Erné, F C; Gee, C N P; Locke, D H; Loebinger, F K; Murphy, P G; Rudge, A; Sens, Johannes C

1973-01-01

Measurements are reported of two-particle correlations in high energy proton-proton collisions with one particle in the pionization region and the other a proton in the fragmentation region. The correlation function is independent of x of the fragmentation proton for 0.55xx. There is an indication that the correlation is an energy-independent function of x. The measurements for two values of the rapidity of the pionization particle give similar results. (11 refs).

Levels of glutamate, aspartate, GABA, and taurine in different regions of the cerebellum after x-irradiation-induced neuronal loss

International Nuclear Information System (INIS)

Rea, M.A.; McBride, W.J.; Rohde, B.H.

1981-01-01

The levels of glutamate (Glu), aspartate (Asp), gamma-amino-n-butyric acid (GABA), and taurine (Tau) were determined in the cortex, molecular layer, and deep nuclei of cerebella of adult rats exposed to X-irradiation at 12-15 days following birth (to prevent the acquisition of late-forming granule cells; 12-15x group) and 8-15 days following birth (to prevent the acquisition of granule and stellate cells; 8-15x group). Also, the levels of the four amino acids were measured in the crude synaptosomal fraction (P2) isolated from the whole cerebella of the control, 12-15x, and 8-15x groups. The level of Glu was significantly decreased by (1) 6-20% in the cerebellar cortex; (2) 15-20% in the molecular layer; and (3) 25-50% in the P2 fraction of the X-irradiated groups relative to control values. The content of Glu in the deep nuclei was not changed by X-irradiation treatment. Regional levels of Asp were unchanged by X-irradiation, while its level in P2 decreased by 15-30% after treatment. The levels of GABA and Tau in the molecular layer, deep nuclei, or P2 were not changed in the experimental groups. However, there was a 15% increase in the levels of GABA and Tau in the cerebellar cortex of the 8-15x group relative to control values. The data support the proposed role of glutamate as the excitatory transmitter released from the cerebellar granule cells but are inconclusive regarding a transmitter role for either Tau or GABA from cerebellar stellate cells

Successive X-class Flares and Coronal Mass Ejections Driven by Shearing Motion and Sunspot Rotation in Active Region NOAA 12673

Science.gov (United States)

Yan, X. L.; Wang, J. C.; Pan, G. M.; Kong, D. F.; Xue, Z. K.; Yang, L. H.; Li, Q. L.; Feng, X. S.

2018-03-01

We present a clear case study on the occurrence of two successive X-class flares, including a decade-class flare (X9.3) and two coronal mass ejections (CMEs) triggered by shearing motion and sunspot rotation in active region NOAA 12673 on 2017 September 6. A shearing motion between the main sunspots with opposite polarities began on September 5 and lasted even after the second X-class flare on September 6. Moreover, the main sunspot with negative polarity rotated around its umbral center, and another main sunspot with positive polarity also exhibited a slow rotation. The sunspot with negative polarity at the northwest of the active region also began to rotate counterclockwise before the onset of the first X-class flare, which is related to the formation of the second S-shaped structure. The successive formation and eruption of two S-shaped structures were closely related to the counterclockwise rotation of the three sunspots. The existence of a flux rope is found prior to the onset of two flares by using nonlinear force-free field extrapolation based on the vector magnetograms observed by Solar Dynamics Observatory/Helioseismic and Magnetic Image. The first flux rope corresponds to the first S-shaped structures mentioned above. The second S-shaped structure was formed after the eruption of the first flux rope. These results suggest that a shearing motion and sunspot rotation play an important role in the buildup of the free energy and the formation of flux ropes in the corona that produces solar flares and CMEs.

Synchrotron radiation effect in the soft x-ray region on the surface properties of pyromellitic dianhydride-oxydianline polyimide

International Nuclear Information System (INIS)

Kato, Yuri; Kanda, Kazuhiro; Haruyama, Yuichi; Matsui, Shinji

2004-01-01

The surface modification of a polyimide (PI) sheet using synchrotron radiation (SR) was carried out. The PI sheet was irradiated to white radiation ranging between 50-1000 eV in a vacuum chamber. The contact angle of the PI surface with a water droplet was found to decrease from 75deg to 58deg by the SR irradiation. The variation of chemical components of the PI surface was studied using X-ray photoelectron spectroscopy (XPS). The ratio of peak intensity from the Ols orbital to that from the Cls orbital increased remarkably by SR irradiation. The increase of wettability on the PI surface was ascribable to the production of an O-rich surface by SR irradiation in the soft X-ray region. (author)

X-ray masks

International Nuclear Information System (INIS)

Greenwood, J.C.; Satchell, D.W.

1984-01-01

In semiconductor manufacture, where X-ray irradiation is used, a thin silicon membrane can be used as an X-ray mask. This membrane has areas on which are patterns to define the regions to be irradiated. These regions are of antireflection material. With the thin, in the order of 3 microns, membranes used, fragility is a problem. Hence a number of ribs of silicon are formed integral with the membrane, and which are relatively thick, 5 to 10 microns. The ribs may be formed by localised deeper boron deposition followed by a selective etch. (author)

Destruction of PAHs by X-Rays in circumnuclear regions of AGNs

Science.gov (United States)

Monfredini, T.; Wolff, W.; Boechat-Roberty, H. M.; Sales, D. A.; Pastoriza, M. G.

2017-07-01

Emission bands associated with PAH molecules are observed in the direction of some classes of AGNs like Seyfert 2, LINERs and obscured quasars (e.g. Kaneda et al., 2008, Sansigre et al., 2008 and Sales et al. 2013). The molecular stability in these environments suggest the presence of very dense gas (˜ 1023-24 cm-2) to shield the cloud of PAHs against X-ray radiation (Voit, 1992, Tielens, 2011, Sales et al., 2013). We examined the photochemistry of simple PAHs: naphtalene (C10H8), anthracene (C14H10), methyl-anthracene (C15H12) and pyrene (C16H10) at the photon energies of 275 eV, 310 eV, 1900 eV and 2500 eV in order to apply the findings at the AGN scenario. The absolute single and double photoionization and photodissociation cross sections were determined for each molecule at each energy. Their ionization and destruction induced by X-rays were examined in the conditions of the circumnuclear region of NGC 1808, a Seyfert 2 galaxy, where PAH emission was detected at 26 pc from the central object (Sales et al., 2013). It was verified the higher photostability of PAHs without functional groups attached. At higher photon energies, the results suggest a higher production yield of double charged PAHs in comparision with the single charged ones (e.g., 2 × higher for double ionized naphtalene at 2500 eV). The production of double charged molecules increase with the size of the molecules. We also discuss a minimum formation rate of PAH to balance the photodestruction rate and maintain a minimum density for their detection (e.g. 4,0× 10-7 M⊙ year-1 for a column density NH of 1023 cm-2 at 26 pc).

Phase equilibria in M-X-X' and M-Al-X ternary systems (M-transition metal, X,X'-B,C,N,Si) and crystal chemistry of ternary compounds

International Nuclear Information System (INIS)

Gusev, A.I.

1996-01-01

The data on phase equilibria in the M-X-X' and M-Al-X ternary systems (M-transition metal of 3 to 8 groups, X-B,C, N, Si) have been considered and summarized. modern oxygen-free advanced ceramics is based on these ternary systems. Phase diagrams of the 130 ternary systems have been discussed, more than two hundred ternary phases forming in these systems have been systematized and described. The typical crystal structures of ternary compounds and phase have been considered, the common and distinctive features of these structures have been analysed. It has been shown that the ternary compounds with octahedral atomic groups XM 6 have a regions of homogeneity. Refs. 240

The spectral and temporal behavior of the variable X-ray binary star Cyg X-1 in the hard region of X-radiation

International Nuclear Information System (INIS)

Steinle, H.

1981-01-01

In the present work the measurements of the X-ray spectrum of Cyg X-1 in the energy range 15 to 160 keV in the years 1975, 1976, 1977 are investigated. The measurements are of such a good quality, that a simple power spectrum as the best fit of a model to the data of Cyg X-1 can be excluded because the spectrum breaks off in the range 70-100 keV. The model of Sunyaev and Titarchuk which describes the comptonizing of protons will low energy in a hot plasma is used first time for filling to the Cyg X-1 spectra and it is seen, that the shape of the spectrum is represented in an excellent manner. From the parameters of the best fit to the spectrum from 1977 an electron temperature of 3.4 x 10 8 K and an optical depth tau = 5 for the plasma in which the photons are scattered are found. (orig./WB) [de

High energy X-ray observation of Cyg X-3

International Nuclear Information System (INIS)

Kendziorra, E.; Pietsch, W.; Staubert, R.; Truemper, J.

1975-01-01

On Feb. 20, 1975 Cyg X-3 was observed in the energy range of 29-70 keV during a 5 hour observation of the Cyg region. An intensity variation consistent with a 4.8 h sinusoidal modulation has been found, in phase with low energy X-ray observations and with a relative amplitude of 0.37 +- 0.19. (orig.) [de

Higher twist contributions to the structure functions Fp2(x,Q2) and Fd2(x,Q2) at large x at higher orders

International Nuclear Information System (INIS)

Bluemlein, J.; Boettcher, H.

2008-02-01

The higher twist contributions to the deeply inelastic structure functions F p 2 (x,Q 2 ) and F d 2 (x,Q 2 ) for larger values of the Bjorken variable x are extracted extrapolating the twist-2 contributions measured in the large W 2 region to the region 4 GeV 2 ≤W 2 ≤12.5 GeV 2 applying target mass corrections. We compare the results for the NLO, NNLO and N 3 LO analyzes and include also the large x at N 4 LO to the Wilson coefficients. A gradual lowering of the higher twist contributions going from NLO to N 4 LO is observed, which stresses the importance of higher order corrections. (orig.)

Strong selective sweeps associated with ampliconic regions in great ape X chromosomes

DEFF Research Database (Denmark)

Nam, Kiwoong; Munch, Kasper; Hobolth, Asger

2014-01-01

The unique inheritance pattern of X chromosomes makes them preferential targets of adaptive evolution. We here investigate natural selection on the X chromosome in all species of great apes. We find that diversity is more strongly reduced around genes on the X compared with autosomes...... with ampliconic sequences we propose that intra-genomic conflict between the X and the Y chromosomes is a major driver of X chromosome evolution....

Multielement analysis of X-Ray fluorescence of Nerium oleander L. Leaves in metropolitan region of Rio de Janeiro

Energy Technology Data Exchange (ETDEWEB)

Santos, Ramon S.; Sanches, Francis Anna C.R.A.; Neves, Arthur O.P.; Oliveira, Davi F.; Anjos, Marcelino J., E-mail: ramonziosp@yahoo.com.br, E-mail: francissanches@gmail.com, E-mail: arthur.nevess@yahoo.com.br, E-mail: davi.oliveira@uerj.br, E-mail: marcelin@uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Instituto de Fisica. Departamento de Fisica Aplicada e Termodinamica

2015-07-01

Some plants are used in the detection of the air pollutants due to leaves ability to absorb the pollutants through their stomata and the cuticle, thus, the plants leaves work as a natural sample of the air emissions that are deposited in their self. However, the foliar analysis of these vegetal species can be used to environmental monitoring. The Nerium oleander L. is a specie of plant commonly used as an environmental biomonitor. In this study, Nerium oleander L. leaves were used as biomonitors to evaluate the levels of environmental pollutants in a sub-region in the Metropolitan Region of Rio de Janeiro-Brazil through Energy Dispersive X-ray Fluorescence technique - EDXRF. The EDXRF system was developed in the own laboratory and consist of a portable XRF system formed by a mini X-ray tube of low power (anode of Ag and operated in 15 kV/50 μA and 35 kV/50 μA) and a SiPIN detector. Samples of Nerium oleander L. were collected from adult plants drawn randomly so as not favoring one side of the plant. The samples were collected during the year seasons (summer and winter). It was detected the concentration of 13 elements: S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba and Pb, and obtain elemental maps of the regions of study. The study shows that the use of EDXRF technique associated to the Nerium oleander L. leaves used as biomonitor is an efficient, precise, fast and low-cost option for air pollutants analysis. (author)

Multielement analysis of X-Ray fluorescence of Nerium oleander L. Leaves in metropolitan region of Rio de Janeiro

International Nuclear Information System (INIS)

Santos, Ramon S.; Sanches, Francis Anna C.R.A.; Neves, Arthur O.P.; Oliveira, Davi F.; Anjos, Marcelino J.

2015-01-01

Some plants are used in the detection of the air pollutants due to leaves ability to absorb the pollutants through their stomata and the cuticle, thus, the plants leaves work as a natural sample of the air emissions that are deposited in their self. However, the foliar analysis of these vegetal species can be used to environmental monitoring. The Nerium oleander L. is a specie of plant commonly used as an environmental biomonitor. In this study, Nerium oleander L. leaves were used as biomonitors to evaluate the levels of environmental pollutants in a sub-region in the Metropolitan Region of Rio de Janeiro-Brazil through Energy Dispersive X-ray Fluorescence technique - EDXRF. The EDXRF system was developed in the own laboratory and consist of a portable XRF system formed by a mini X-ray tube of low power (anode of Ag and operated in 15 kV/50 μA and 35 kV/50 μA) and a SiPIN detector. Samples of Nerium oleander L. were collected from adult plants drawn randomly so as not favoring one side of the plant. The samples were collected during the year seasons (summer and winter). It was detected the concentration of 13 elements: S, Cl, K, Ca, Mn, Fe, Cu, Zn, Br, Rb, Sr, Ba and Pb, and obtain elemental maps of the regions of study. The study shows that the use of EDXRF technique associated to the Nerium oleander L. leaves used as biomonitor is an efficient, precise, fast and low-cost option for air pollutants analysis. (author)

Producing x-rays

International Nuclear Information System (INIS)

Mallozzi, P.J.; Epstein, H.M.; Jung, R.G.; Applebaum, D.C.; Fairand, B.P.; Gallagher, W.J.

1977-01-01

A method of producing x-rays by directing radiant energy from a laser onto a target is described. Conversion efficiency of at least about 3 percent is obtained by providing the radiant energy in a low-power precursor pulse of approximately uniform effective intensity focused onto the surface of the target for about 1 to 30 nanoseconds so as to generate an expanding unconfined coronal plasma having less than normal solid density throughout and comprising a low-density (underdense) region wherein the plasma frequency is less than the laser radiation frequency and a higher-density (overdense) region wherein the plasma frequency is greater than the laser radiation frequency and, about 1 to 30 nanoseconds after the precursor pulse strikes the target, a higher-power main pulse focused onto the plasma for about 10 -3 to 30 nanoseconds and having such power density and total energy that the radiant energy is absorbed in the underdense region and conducted into the overdense region to heat it and thus to produce x-rays therefrom with the plasma remaining substantially below normal solid density and thus facilitating the substantial emission of x-rays in the form of spectral lines arising from nonequilibrium ionization states

Very Large Array H I Zeeman Observations of the Cygnus X Region: DR 22 and ON 2

Science.gov (United States)

Mayo, E. A.; Troland, T. H.

2012-02-01

We have used the Very Large Array to study the Zeeman effect in 21 cm H I absorption lines from two star-forming regions in the Cygnus X complex, DR 22 and ON 2. We measure the line-of-sight magnetic field toward these regions, finding B los = -84 ± 11 μG toward the DR 22 H II region and B los < 50 μG toward each of the two H II regions in ON 2. We interpret these results in terms of two different models. In one model, we assume that the H I Zeeman effect is a measure of magnetic fields in the associated molecular clouds. If so, then the DR 22 molecular cloud is magnetically subcritical, that is, magnetically dominated. The ON 2 molecular clouds are magnetically supercritical. In a second model, we assume that the H I Zeeman effect is a measure of magnetic fields in photon-dominated regions where the gas has been compressed (and the field amplified) by absorption of stellar radiation. We find that this second model, where the measured field strength has been affected by star formation, accounts well for the DR 22 H I Zeeman effect. This same model, however, overpredicts the magnetic field in ON 2. ON 2 may be a region where the magnetic field is energetically insignificant or where the field happens to lie nearly in the plane of the sky.

NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources

DEFF Research Database (Denmark)

Hong, JaeSub; Mori, Kaya; Hailey, Charles J.

2016-01-01

persistent luminous X-ray binaries (XBs) and the likely run-away pulsar called the Cannonball. New source-detection significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr. A diffuse complex with no clear soft X-ray counterparts. The severe extinction observed in the Chandra spectra...

Distortion of absorption-line velocity curves due to x-ray heating in x-ray binaries

International Nuclear Information System (INIS)

Milgrom, M.

1976-01-01

The effects of X-ray heating on the measured absorption line velocities, in X-ray binaries with low X-rays to optical luminosities ratio are considered. These effects may be appreciable even for such binaries where the effect of X-ray heating on the light-curve is negligible. The effects are studied qualitatively and suggest possible ways to partially eliminate the systematic errors introduced by them. The individual systems Cyg x-1 and SMC x-1 are treated and the results of numerical calculations are presented for them. For Cyg x-1 it is found that the effect is detectable during the X-ray 'high' state in all regions of the spectrum. During the 'low' state it may be important in the red region of the spectrum. The results for the case in which soft X-ray fluxes (E < or approximately .4 keV, suggested by theoretical models) are present are also given. For SMC x-1 a strong effect for Hα, Hβ, Hγ had been found. This effect may be responsible for the observed variable velocity curve. We also find for SMC x-1 that the average X-ray intensity falling on the primary must be considerably smaller than what is derived from the detected flux, or else the effect is too large. (author)

X-ray optics and X-ray microscopes: new challenges

International Nuclear Information System (INIS)

Susini, J.

2004-01-01

Soon after the discovery of X-rays in 1895 by W. Roentgen, it became rapidly clear that the methods traditionally used in the visible light regime, namely refraction, diffraction and reflection were difficult to apply for X-ray optics. The physical origins of these difficulties are closely linked to the very nature of interaction of X-rays with matter. The small deviation δ of the refractive index of condensed matter from unity makes it difficult to extend refraction-based optics from the optical spectral region to the X-ray region because the refraction angle is proportional to δ. Similarly it is very challenging to extend diffraction-based focusing techniques to X-rays because the diffraction angle scales inversely with wavelength. Finally, the use of reflection-based optics is also limited by the very small critical angle for total reflection. All those fundamental limitations prevented for almost one century, the development of X-ray microscopy whereas electron microscopy became a standard tool. In the past twenty years, interests for X-ray microscopy revived, mainly because of several major advances in X-ray sources and X-ray optics. X-ray microscopy techniques are now emerging as powerful and complementary tools for submicron investigations. Soft X-ray microscopes offer traditionally the possibility to form direct images of thick hydrated biological material in near-native environment, at a spatial resolution well beyond that achievable with visible light microscopy. Natural contrast is available in the soft X-ray region, in the so-called ''water-window'', due to the presence of absorption edges of the major constituents (C,N,O). Recent advances in manufacturing techniques have enlarged the accessible energy range of micro-focussing optics and offer new applications in a broad range of disciplines. X-ray microscopy in the 1 - 30 keV energy range is better suited for fluorescence to map trace elements, tomography for 3D imaging and micro-diffraction. The

Magnetic and crystallographic properties of Gd(Cu/sub 1-x/Ni/sub x/)2 and Gd(Cu/sub 1-x/Al/sub x/)2 intermetallic compounds

International Nuclear Information System (INIS)

Borombaev, M.K.; Levitin, R.Z.; Markosyan, A.S.; Snegirev, V.V.

1986-01-01

Magnetization, paramagnetic susceptibility, and temperature dependence of lattice parameters of Gd(Cu/sub 1-x/Ni/sub x/) 2 (0 2 (0 2 -type structure have been studied in a wide range of temperatures. Below the ordering temperature anomalies in thermal expansion along the crystallographic axes a, b, and c enabled to distinguish between various types of magnetic arrangements. The Gd(Cu/sub 1-x/Ni/sub x/) 2 system has two types of antiferromagnetic phases: AF1 (0 = 0.13 the system orders ferromagnetically. In the Gd(Cu/sub 1-x/Al/sub x/) 2 system two magnetic phases AF1 and AF3 occur in the concentration regions 0 <= x <= 0.035 and 0.04 <= x <= 0.07, respectively. The obtained results are discussed in terms of the RKKY model via the changing conduction electron concentration. (author)

Open magnetic fields in active regions

Science.gov (United States)

Svestka, Z.; Solodyna, C. V.; Howard, R.; Levine, R. H.

1977-01-01

Soft X-ray images and magnetograms of several active regions and coronal holes are examined which support the interpretation that some of the dark X-ray gaps seen between interconnecting loops and inner cores of active regions are foot points of open field lines inside the active regions. Characteristics of the investigated dark gaps are summarized. All the active regions with dark X-ray gaps at the proper place and with the correct polarity predicted by global potential extrapolation of photospheric magnetic fields are shown to be old active regions, indicating that field opening is accomplished only in a late phase of active-region development. It is noted that some of the observed dark gaps probably have nothing in common with open fields, but are either due to the decreased temperature in low-lying portions of interconnecting loops or are the roots of higher and less dense or cooler loops.

X-ray diffraction and dielectric studies across morphotropic phase boundary in (1 - x) [Pb(Mg0.5W0.5)O3]-xPbTiO3 ceramics

International Nuclear Information System (INIS)

Singh, A.K.; Singh, Akhilesh Kumar

2011-01-01

Research highlights: → Structural studies reveal pseudocubic structure of PMW-xPT for the x ≤ 0.42, tetragonal for the x ≥ 0.72 and the coexistences of the two phases for intermediate compositions (0.46 ≤ x 0.68). → Temperature dependent dielectric constant for compositions in the two phase region shows two dielectric anomalies above room temperature and not just one as reported by earlier workers. → Rietveld structural analysis of PMW-xPT ceramics is presented for the first time to determine the fraction of the coexisting phases in MPB region. - Abstract: We present here the results of comprehensive X-ray diffraction and dielectric studies on several compositions of (1 - x)[Pb(Mg 0.5 W 0.5 )O 3 ]-xPbTiO 3 (PMW-xPT) solid solution across the morphotropic phase boundary. Rietveld analysis of the powder X-ray diffraction data reveals cubic (space group Fm3m) structure of PMW-xPT ceramics for the compositions with x ≤ 0.42, tetragonal (space group P4mm) structure for the compositions with x ≥ 0.72 and coexistence of the tetragonal and cubic phases for the intermediate compositions (0.46 ≤ x ≤ 0.68). Temperature dependence of the dielectric permittivity above room temperature exhibits diffuse nature of phase transitions for the compositions in the cubic and two phase region while the compositions with tetragonal structure at room temperature exhibit sharp ferroelectric to paraelectric phase transition. The PMW-xPT compositions with coexistence of tetragonal and cubic phases at room temperature exhibit two anomalies in the temperature dependence of the dielectric permittivity above room temperature. Using results of structural and dielectric studies a partial phase diagram of PMW-xPT ceramics is also presented.

Novel transparent conducting oxide: Anatase Ti1-xNb xO2

International Nuclear Information System (INIS)

Furubayashi, Yutaka; Hitosugi, Taro; Yamamoto, Yukio; Hirose, Yasushi; Kinoda, Go; Inaba, Kazuhisa; Shimada, Toshihiro; Hasegawa, Tetsuya

2006-01-01

Single-crystalline Ti 1-x Nb x O 2 (x = 0.2) films of 40 nm thickness were deposited on SrTiO 3 (100) substrates by the pulsed laser deposition (PLD) technique. X-ray diffraction measurement confirmed epitaxial growth of anatase (001) film. The resistivity of Ti 1-x Nb x O 2 films with x ≥ 0.03 is 2-3 x 10 -4 Ω cm at room temperature. The carrier density of Ti 1-x Nb x O 2 , which is almost proportional to the Nb concentration, can be controlled in a range of 1 x 10 19 to 2 x 10 21 cm -3 . Optical measurements revealed that internal transmittance in the visible and near-infrared region for films with x = 0.03 was more than 97%. These results demonstrate that the presently developed anatase Ti 1-x Nb x O 2 is one of the promising candidates for the practical TCOs

A Deep Chandra ACIS Study of NGC 4151. I. The X-ray Morphology of the 3 kpc Diameter Circum-nuclear Region and Relation to the Cold Interstellar Medium

Science.gov (United States)

Wang, Junfeng; Fabbiano, Giuseppina; Risaliti, Guido; Elvis, Martin; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.; Dumas, Gaelle; Schinnerer, Eva

2011-03-01

We report on the imaging analysis of ~200 ks sub-arcsecond resolution Chandra Advanced CCD Imaging Spectrometer (ACIS-S) observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the southwest from the nucleus, much farther than seen in earlier X-ray studies. The terminus of the northeastern X-ray emission is spatially coincident with a CO gas lane, where the outflow likely encounters dense gas in the host galactic disk. X-ray emission is also detected outside the boundaries of the ionization cone, which indicates that the gas there is not completely shielded from the nuclear continuum, as would be the case for a molecular torus collimating the bicone. In the central r < 200 pc region, the subpixel processing of the ACIS data recovers the morphological details on scales of <30 pc (<0farcs5) first discovered in Chandra High Resolution Camera images. The X-ray emission is more absorbed toward the boundaries of the ionization cone, as well as perpendicular to the bicone along the direction of a putative torus in NGC 4151. The innermost region where X-ray emission shows the highest hardness ratio is spatially coincident with the near-infrared-resolved H2 emission and dusty spirals we find in an Hubble Space Telescope V - H color image. The agreement between the observed H2 line flux and the value predicted from X-ray-irradiated molecular cloud models supports photo-excitation by X-rays from the active nucleus as the origin of the H2 line, although contribution from UV fluorescence or collisional excitation cannot be ruled out with current data. The discrepancy between the mass of cold molecular gas inferred from recent CO and near-infrared H2 observations may be explained by the anomalous CO abundance in this X-ray-dominated region. The total H2 mass derived from the X-ray observation agrees with the recent measurement by Storchi-Bergmann et al.

Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens

International Nuclear Information System (INIS)

Emoto, T.; Sato, Y.; Konishi, Y.; Ding, X.; Tsuji, K.

2004-01-01

A polycapillary X-ray lens is an effective optics to obtain a μm-size X-ray beam for micro-X-ray fluorescence spectrometry (μ-XRF). We developed a μ-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit μ-XRF (GE-μ-XRF). The evaluated diameter of the primary X-ray beam was 48 μm at the focal distance of the X-ray lens. Use of this instrument enabled two-dimensional mapping of the elemental distributions during growth of the plant 'Quinoa'. The results of the mapping revealed elemental transition during growth. In addition, a small region of thin film was analyzed by GE-μ-XRF. We expect that GE-μ-XRF will become an effective method of estimating the film thickness of a small region

Infrared Spectroscopy in the region X-Ray Diffraction and the mineral trioxide aggregate

International Nuclear Information System (INIS)

Barros, C.M.B.; Oliveira, S.V.; Silva, M.C.; Cartaxo, J.M.; Fook, M.V.L.

2011-01-01

In the nineties was introduced into the search field of biomaterials to mineral trioxide aggregate (MTA). It is a derivative of Portland cement with similar chemical properties and was initially developed as a root filling material in dentistry. This material is presented characteristics of mechanical, physical and biological meaningful when applied to biological environment. It was used to search a commercial MTA manipulated with distilled water and propylene glycol in order to verify chemical composition, infrared absorption bands and stages in the samples. The MTA has been characterized by XRF, XRD and FTIR. In X-ray fluorescence was found that the MTA has a characteristic composition of hydraulic cement. Through FTIR MTA mixed with water presents an enlargement in the absorption bands in the region 1467 and 873 cm-1. By means of XRD showed that there is no presence of toxic materials in the majority and secondary phases. (author)

Low temperature hopping conduction in amorphous Gesub(x)Sesub(1-x)

International Nuclear Information System (INIS)

Mehra, R.M.; Kumar, H.; Agarwal, S.C.; Sikka, P.; Mathur, P.C.

1985-08-01

Bulk amorphous samples of Gesub(x)Sesub(1-x) (0.5<=x<=0.7) were prepared by quenching. Dc conductivity measurements were carried out in the temperature range 77-300 K. In the low temperature region, the conduction occurs due to variable range hopping in the localized states near the Fermi level. The results are explained by Mott, Pollak and Butcher's models. Butcher's model which is based on the equivalent of conduction network is compatible with the results. (author)

Mapping of auroral x-rays from rocket overflights

International Nuclear Information System (INIS)

Goldberg, R.A.; Barcus, J.R.; Treinish, L.A.; Vondrak, R.R.

1982-01-01

In March 1978, two Nike Tomahawk payloads were launched from Poker Flat, Alaska, to observe the structure of bremsstrhlung x rays and precipitating particles during both nighttime and daytime observe x rays in four spectral ranges (5--10 keV, 10--20 keV, 20--40 keV, and >40 keV). Particle contamination of the detectors was avoided with broom magnet shielding techniques. By virtue of the payloads' approximate 20 0 coning angle (about 10.5-s period), the detectors scanned wide regions on either side of the trajectory paths. This has permitted construction (using computer color graphics) of the time averaged (approx.4 min) x ray source regions near 100 km, a height consistent with Chatanika radar electron density maps obtained during each flight period. X ray image maps for both flights exhibit enhanced source regions well outside the rocket trajectory planes. For the nighttime overflight, Chatanika radar scan data and Fort Yukon riometer data were used to verify the presence of an x ray imaged enhancement of electron precipitation, approximately 30 km to the east of the rocket trajectory plane. The daytime x ray data also exhibited several regions of enhanced emission, but outside the region scanned by Chatanika radar. A comparison of the x ray emissions from the two events shows the daytime x ray spectral distributions to be significantly harder but less intense that the nighttime distributions. Furthermore, for both events, spectra compared within and nearby each enhanced emitting region exhibit characteristics of a two component spectrum, such that the bright regions show an increased flux primarily in the low-energy component. Electron fluxes measured on each of the two flights with Geiger tubes are mainly isotropic over the downward hemisphere at night but show anisotropic pitch angle characteristics by day, consistent with the concept that the enhancement of the low-energy x ray flux component is predominantly induced by electrons filling the loss cone

X-RAY SIGNATURES OF NON-EQUILIBRIUM IONIZATION EFFECTS IN GALAXY CLUSTER ACCRETION SHOCK REGIONS

International Nuclear Information System (INIS)

Wong, Ka-Wah; Sarazin, Craig L.; Ji Li

2011-01-01

The densities in the outer regions of clusters of galaxies are very low, and the collisional timescales are very long. As a result, heavy elements will be under-ionized after they have passed through the accretion shock. We have studied systematically the effects of non-equilibrium ionization for relaxed clusters in the ΛCDM cosmology using one-dimensional hydrodynamic simulations. We found that non-equilibrium ionization effects do not depend on cluster mass, but depend strongly on redshift which can be understood by self-similar scaling arguments. The effects are stronger for clusters at lower redshifts. We present X-ray signatures such as surface brightness profiles and emission lines in detail for a massive cluster at low redshift. In general, soft emission (0.3-1.0 keV) is enhanced significantly by under-ionization, and the enhancement can be nearly an order of magnitude near the shock radius. The most prominent non-equilibrium ionization signature we found is the O VII and O VIII line ratio. The ratios for non-equilibrium ionization and collisional ionization equilibrium models are different by more than an order of magnitude at radii beyond half of the shock radius. These non-equilibrium ionization signatures are equally strong for models with different non-adiabatic shock electron heating efficiencies. We have also calculated the detectability of the O VII and O VIII lines with the future International X-ray Observatory (IXO). Depending on the line ratio measured, we conclude that an exposure of ∼130-380 ks on a moderate-redshift, massive regular cluster with the X-ray Microcalorimeter Spectrometer (XMS) on the IXO will be sufficient to provide a strong test for the non-equilibrium ionization model.

Radiometer evaluation of X-rays equipment in the region of Aracatuba, Sao Paulo, Brazil

International Nuclear Information System (INIS)

Fernandes, Marco A.R.

2009-01-01

This paper presents the basic concepts of radiation protection to guide the health care professionals who use equipment emitting ionizing radiation on the correct handling of the beams of radiation. Radiometric evaluations were conducted in 1665 in X-ray equipment, installed in dental surgeries and clinics, hospitals and radiology services, during the years 1996 to 2003 in the region of Aracatuba. Tests of radiometry are presented as a technical report where the parameters are quantified physical and radiological verifying its compliance with the established by legislation. The distribution of reports by type of unit shows that the vast majority of equipment is of periapical dental x-rays (72%), 25% of equipment is medical equipment for radiology and 3% is dental equipment panoramic model (orthodontic documentation). Among the physical parameters analyzed, the length of the browser was showing more variance compared to the required by law, this fact may also contribute to gaps in the rate of the radiation dose and the size of field in the skin of the patient, the that can easily be resolved simply to replace the piece at the outlet of the head. During the completion of visits to services, it also noted a gap in the training of professionals who operate this equipment emitting radiation, warning of the need for specific training in the area. (author)

Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens

Energy Technology Data Exchange (ETDEWEB)

Emoto, T.; Sato, Y.; Konishi, Y.; Ding, X.; Tsuji, K. E-mail: tsuji@a-chem.eng.osaka-cu.ac.jp

2004-08-31

A polycapillary X-ray lens is an effective optics to obtain a {mu}m-size X-ray beam for micro-X-ray fluorescence spectrometry ({mu}-XRF). We developed a {mu}-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit {mu}-XRF (GE-{mu}-XRF). The evaluated diameter of the primary X-ray beam was 48 {mu}m at the focal distance of the X-ray lens. Use of this instrument enabled two-dimensional mapping of the elemental distributions during growth of the plant 'Quinoa'. The results of the mapping revealed elemental transition during growth. In addition, a small region of thin film was analyzed by GE-{mu}-XRF. We expect that GE-{mu}-XRF will become an effective method of estimating the film thickness of a small region.

Analysis of Ti valence states in resistive switching regions of a rutile TiO2‑ x four-terminal memristive device

Science.gov (United States)

Yamaguchi, Kengo; Takeuchi, Shotaro; Tohei, Tetsuya; Ikarashi, Nobuyuki; Sakai, Akira

2018-06-01

We have performed Ti valence state analysis of our four-terminal rutile TiO2‑ x single-crystal memristors using scanning transmission electron microscopy–electron energy loss spectroscopy (STEM–EELS). Analysis of Ti-L2,3 edge EELS spectra revealed that the electrocolored region formed by the application of voltage includes a valence state reflecting highly reduced TiO2‑ x due to the accumulation of oxygen vacancies. Such a valence state mainly exists within ∼50 nm from the crystal surface and extends along specific crystal directions. These electrically reduced surface layers are considered to directly contribute to the resistive switching (RS) in the four-terminal device. The present results add new insights into the microscopic mechanisms of the RS phenomena and should contribute to further development and improvements of TiO2‑ x based memristive devices.

Active region structures in the transition region and corona

International Nuclear Information System (INIS)

Webb, D.F.

1981-01-01

Observational aspects of the transition region and coronal structures of the solar active region are reviewed with an emphasis on imaging of the plasma loops which act as tracers of the magnetic flux loops. The study of the basic structure of an active region is discussed in terms of the morphological and thermal classifications of active region loops, including umbral structures, and observational knowledge of the thermal structure of loops is considered in relation to scaling laws, emission measures and the structures of individual loops. The temporal evolution of active region loop structures is reviewed with emphasis on ephemeral regions and the emergence of active regions. Planned future spaceborne observations of active region loop structures in the EUV and soft X-ray regions are also indicated

CubeX: The CubeSAT X-ray Telescope for Elemental Abundance Mapping of Airless Bodies and X-ray Pulsar Navigation

Science.gov (United States)

Nittler, L. R.; Hong, J.; Kenter, A.; Romaine, S.; Allen, B.; Kraft, R.; Masterson, R.; Elvis, M.; Gendreau, K.; Crawford, I.; Binzel, R.; Boynton, W. V.; Grindlay, J.; Ramsey, B.

2017-12-01

The surface elemental composition of a planetary body provides crucial information about its origin, geological evolution, and surface processing, all of which can in turn provide information about solar system evolution as a whole. Remote sensing X-ray fluorescence (XRF) spectroscopy has been used successfully to probe the major-element compositions of airless bodies in the inner solar system, including the Moon, near-Earth asteroids, and Mercury. The CubeSAT X-ray Telescope (CubeX) is a concept for a 6U planetary X-ray telescope (36U with S/C), which utilizes Miniature Wolter-I X-ray optics (MiXO), monolithic CMOS and SDD X-ray sensors for the focal plane, and a Solar X-ray Monitor (heritage from the REXIS XRF instrument on NASA's OSIRIS-REx mission). CubeX will map the surface elemental composition of diverse airless bodies by spectral measurement of XRF excited by solar X-rays. The lightweight ( 1 kg) MiXO optics provide sub-arcminute resolution with low background, while the inherently rad-hard CMOS detectors provide improved spectral resolution ( 150 eV) at 0 °C. CubeX will also demonstrate X-ray pulsar timing based deep space navigation (XNAV). Successful XNAV will enable autonomous deep navigation with little to no support from the Deep Space Network, hence lowering the operation cost for many more planetary missions. Recently selected by NASA Planetary Science Deep Space SmallSat Studies, the first CubeX concept, designed to rideshare to the Moon as a secondary spacecraft on a primary mission, is under study in collaboration with the Mission Design Center at NASA Ames Research Center. From high altitude ( 6,000 km) frozen polar circular orbits, CubeX will study > 8 regions ( 110 km) of geological interest on the Moon over one year to produce a high resolution ( 2-3 km) elemental abundance map of each region. The novel focal plane design of CubeX also allows us to evaluate the performance of absolute navigation by sequential observations of several

Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region

International Nuclear Information System (INIS)

Tanaka, Kenichiro; Miyahara, Tsuneaki

1987-02-01

This report is the summary of the contents of the study meeting 'Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region' sponsored by PF, held on October 20 and 21, 1986. This study meeting was held by inviting those who are particularly interested in the basic field among the users of VUV and soft x-ray region, and the research on the application field was excluded. The objective of the discussion of this study meeting was to talk about the dream that if a high luminance light source which is 100 - 1000 times more intense in terms of luminous flux intensity is completed, what can we do with it. Three sessions on the themes 'How the existing research fields will develop', 'What the possible new research fields are' and 'Comment from the technical aspect' were held. More than seven years elapsed since the beginning of construction of the Photon Factory. Many excellent results have been obtained. As of October, 1986, the beam lines available for experiment are 11, the themes of common utilization experiment in progress are 300, and the number of registered researchers exceeded 1000. The development of a new light emission source is to be undertaken. (Kako, I.)

High Reflectance Nanoscale V/Sc Multilayer for Soft X-ray Water Window Region.

Science.gov (United States)

Huang, Qiushi; Yi, Qiang; Cao, Zhaodong; Qi, Runze; Loch, Rolf A; Jonnard, Philippe; Wu, Meiyi; Giglia, Angelo; Li, Wenbin; Louis, Eric; Bijkerk, Fred; Zhang, Zhong; Wang, Zhanshan

2017-10-10

V/Sc multilayer is experimentally demonstrated for the first time as a high reflectance mirror for the soft X-ray water window region. It primarily works at above the Sc-L edge (λ = 3.11 nm) under near normal incidence while a second peak appears at above the V-L edge (λ = 2.42 nm) under grazing incidence. The V/Sc multilayer fabricated with a d-spacing of 1.59 nm and 30 bilayers has a smaller interface width (σ = 0.27 and 0.32 nm) than the conventional used Cr/Sc (σ = 0.28 and 0.47 nm). For V/Sc multilayer with 30 bilayers, the introduction of B 4 C barrier layers has little improvement on the interface structure. As the number of bilayers increasing to 400, the growth morphology and microstructure of the V/Sc layers evolves with slightly increased crystallization. Nevertheless, the surface roughness remains to be 0.25 nm. A maximum soft X-ray reflectance of 18.4% is measured at λ = 3.129 nm at 9° off-normal incidence using the 400-bilayers V/Sc multilayer. According to the fitted model, an s-polarization reflectance of 5.2% can also be expected at λ = 2.425 nm under 40° incidence. Based on the promising experimental results, further improvement of the reflectance can be achieved by using a more stable deposition system, exploring different interface engineering methods and so on.

Photon-response spectrum of surface barrier diodes on GaAssub(1-x)Psub(x) mixed crystals

International Nuclear Information System (INIS)

Omar, O.A.

1981-07-01

Surface barrier diodes have been prepared by chemical deposition of thin gold film on samples of GaAssub(1-x)Psub(x) with x=0.3. The spectrum of the photo-response over a spectral range covering the photo-injection from the metal and the intrinsic absorption regions of the semiconductor has been measured. From the photo-threshold corresponding to each region, the height of the energy barrier and the forbidden gap width of the semiconductor have been determined and are found to be 0.96 e.v. and 1.78 e.v. respectively for the investigated composition. (author)

Selective growth of Ge1- x Sn x epitaxial layer on patterned SiO2/Si substrate by metal-organic chemical vapor deposition

Science.gov (United States)

Takeuchi, Wakana; Washizu, Tomoya; Ike, Shinichi; Nakatsuka, Osamu; Zaima, Shigeaki

2018-01-01

We have investigated the selective growth of a Ge1- x Sn x epitaxial layer on a line/space-patterned SiO2/Si substrate by metal-organic chemical vapor deposition. We examined the behavior of a Sn precursor of tributyl(vinyl)tin (TBVSn) during the growth on Si and SiO2 substrates and investigated the effect of the Sn precursor on the selective growth. The selective growth of the Ge1- x Sn x epitaxial layer was performed under various total pressures and growth temperatures of 300 and 350 °C. The selective growth of the Ge1- x Sn x epitaxial layer on the patterned Si region is achieved at a low total pressure without Ge1- x Sn x growth on the SiO2 region. In addition, we found that the Sn content in the Ge1- x Sn x epitaxial layer increases with width of the SiO2 region for a fixed Si width even with low total pressure. To control the Sn content in the selective growth of the Ge1- x Sn x epitaxial layer, it is important to suppress the decomposition and migration of Sn and Ge precursors.

Search for photon–photon elastic scattering in the X-ray region

International Nuclear Information System (INIS)

Inada, T.; Yamaji, T.; Adachi, S.; Namba, T.; Asai, S.; Kobayashi, T.; Tamasaku, K.; Tanaka, Y.; Inubushi, Y.; Sawada, K.; Yabashi, M.; Ishikawa, T.

2014-01-01

We report the first results of a search for real photon–photon scattering using X rays. A novel system is developed to split and collide X-ray pulses by applying interferometric techniques. A total of 6.5×10 5 pulses (each containing about 10 11 photons) from an X-ray Free-Electron Laser are injected into the system. No scattered events are observed, and an upper limit of 1.7×10 −24  m 2 (95% C.L.) is obtained on the photon–photon elastic scattering cross section at 6.5 keV

Symbiotic Stars in X-rays

Science.gov (United States)

Luna, G. J. M.; Sokoloski, J. L.; Mukai, K.; Nelson, T.

2014-01-01

Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of 9 white dwarf symbiotics that were not previously known to be X-ray sources and one that was previously detected as a supersoft X-ray source. The 9 new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. Swift/XRT detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component, which we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component, which likely arises in a region where low-velocity shocks produce X-ray emission, i.e. a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the alpha/beta/gamma classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new sigma classification for sources with

The fragile X syndrome: Isolation of the FMR-1 gene and characterization of the fragile X mutation

NARCIS (Netherlands)

B.A. Oostra (Ben); A. Verkerk

1992-01-01

markdownabstractConclusion Rapid progress has been made in the analysis of the fragile X syndrome during 1991. Different groups have discovered that fragile X chromosomes are preferentially methylated. In these X chromosomes an insertion has been found in the methylated region. The FMR-1 gene,

Dosage compensation and demasculinization of X chromosomes in Drosophila.

Science.gov (United States)

Bachtrog, Doris; Toda, Nicholas R T; Lockton, Steven

2010-08-24

The X chromosome of Drosophila shows a deficiency of genes with male-biased expression, whereas mammalian X chromosomes are enriched for spermatogenesis genes expressed premeiosis and multicopy testis genes. Meiotic X-inactivation and sexual antagonism can only partly account for these patterns. Here, we show that dosage compensation (DC) in Drosophila may contribute substantially to the depletion of male genes on the X. To equalize expression between X-linked and autosomal genes in the two sexes, male Drosophila hypertranscribe their single X, whereas female mammals silence one of their two X chromosomes. We combine fine-scale mapping data of dosage compensated regions with genome-wide expression profiles and show that most male-biased genes on the D. melanogaster X are located outside dosage compensated regions. Additionally, X-linked genes that have newly acquired male-biased expression in D. melanogaster are less likely to be dosage compensated, and parental X-linked genes that gave rise to an autosomal male-biased retrocopy are more likely located within compensated regions. This suggests that DC contributes to the observed demasculinization of X chromosomes in Drosophila, both by limiting the emergence of male-biased expression patterns of existing X genes, and by contributing to gene trafficking of male genes off the X. Copyright 2010 Elsevier Ltd. All rights reserved.

Study of 25 X-chromosome SNPs in the Portuguese

DEFF Research Database (Denmark)

Pereira, Vania; Tomas Mas, Carmen; Amorim, António

2011-01-01

The importance of X-chromosome markers in individual identifications, population genetics, forensics and kinship testing is getting wide recognition. In this work, we studied the distributions of 25 X-chromosome single nucleotide polymorphisms (X-SNPs) in population samples from Northern, Central...... and Southern Portugal (n=305). The data were also compared with previous data from the Mediterranean area confirming a general genetic homogeneity among populations in the region. The X-SNP distribution in the three Portuguese regional samples did not show any significant substructure and the X...

Structure and magnetic transport properties of GdIn{sub 3−x}Mn{sub x} intermetallics

Energy Technology Data Exchange (ETDEWEB)

He, Qiang; Guo, Yongquan, E-mail: yqguo@ncepu.edu.cn; Liu, Hanyuan

2016-03-01

The crystal structures and magneto-transport properties of GdIn{sub 3−x}Mn{sub x} have been investigated using X-ray diffraction and magnetic and electric measurements. GdIn{sub 3−x}Mn{sub x} crystallize in cubic structure, and their lattice parameters tend to decrease with increasing Mn content due to the size effect at In site by Mn substitution for In. Mn doped GdIn{sub 3−x}Mn{sub x} order antiferromagnetically at low temperature. However, Mn doping into GdIn{sub 3} causes the decrease of Néel temperature due to the distortion of Gd(In,Mn){sub 3} tetrahedron formed by Gd at corners and (In,Mn) at face centers in unit cell. The resistivities of GdIn{sub 3−x}Mn{sub x} are going up with increasing Mn content. The electric phase transition is associated with the magnetic transition, and the magneto-transport follows electron–magnon scattering model in low temperature region and the Stoner spin fluctuation model in high temperature region, respectively. - Highlights: • Novel GdIn{sub 3−x}Mn{sub x} intermetallic compounds have been successfully prepared. • The lattice parameters tend to decrease with increasing Mn content. • GdIn{sub 3−x}Mn{sub x} orders antiferromagnetically at low temperature. • The strong correlation between the electric transport and magnetic state is observed.

Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

Energy Technology Data Exchange (ETDEWEB)

Upadhyay, Ashutosh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2015-04-14

Results of the room temperature structural studies on (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28 ≤ x ≤ 0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4 mm) phases in the composition range 0.33 ≤ x ≤ 0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28 ≤ x ≤ 0.32. The structure for the compositions with x ≥ 0.45 is found to be predominantly tetragonal with space group P4 mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x = .35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

Report of workshop on X-ray and nonlinear optics

International Nuclear Information System (INIS)

Nasu, Keiichiro; Namikawa, Kazumichi

1994-07-01

As synchrotron radiation has advanced to high luminance, the possibility of realizing coherent light has heightened, and the nonlinear optical phenomena in soft and hard X-ray regions have become the object of the concern of X-ray researchers, and also the researchers in the fields of quantum electronics and optical properties. This workshop was held on September 21 and 22, 1993 at National Laboratory for High energy Physics. Lectures were given on the generation of second harmonic of X-ray by utilizing dynamic diffraction, X-ray parametric scattering induced by strong laser beam, the resonance enhancement of X-ray inelastic scattering induced by strong visible light, Raman scattering in soft X-ray region, the control of nonlinear optical processes by strong external field; the experiments, though they are fundamental, they have not been carried out; undulator radiation X-ray and X-ray free electron laser, the improvement of the coherence of X-ray laser, superradiance of Frenkel excitor system and the measurement of superhigh speed pulses in X-ray region. The comment from the standpoint of the research on nonlinear optics was given. In this document, the gists of these lectures are collected. (K.I.)

Report of workshop on X-ray and nonlinear optics

Energy Technology Data Exchange (ETDEWEB)

Nasu, Keiichiro; Namikawa, Kazumichi [eds.

1994-07-01

As synchrotron radiation has advanced to high luminance, the possibility of realizing coherent light has heightened, and the nonlinear optical phenomena in soft and hard X-ray regions have become the object of the concern of X-ray researchers, and also the researchers in the fields of quantum electronics and optical properties. This workshop was held on September 21 and 22, 1993 at National Laboratory for High energy Physics. Lectures were given on the generation of second harmonic of X-ray by utilizing dynamic diffraction, X-ray parametric scattering induced by strong laser beam, the resonance enhancement of X-ray inelastic scattering induced by strong visible light, Raman scattering in soft X-ray region, the control of nonlinear optical processes by strong external field; the experiments, though they are fundamental, they have not been carried out; undulator radiation X-ray and X-ray free electron laser, the improvement of the coherence of X-ray laser, superradiance of Frenkel excitor system and the measurement of superhigh speed pulses in X-ray region. The comment from the standpoint of the research on nonlinear optics was given. In this document, the gists of these lectures are collected. (K.I.).

Present status of research and development on X-ray microprobe

International Nuclear Information System (INIS)

Koike, Masaki; Suzuki, I.H.

1991-01-01

X-ray beam micro-analysis has advanced rapidly in these years in conjunction with the development of powerful X-ray sources. Among a variety of methods being attempted, the method using a collimated narrow beam has been important because of high brightness, and of usability in both regions of soft and hard X-rays. In the soft X-ray region, the focused beam is formed by a fresnel zone plate or a Schwaltzschild mirror assembly, and can be used for scanning transmission microscope or scanning photoelectron microscope. In the hard X-ray region, the beam is formed by grazing incidence mirrors, and can be used for X-ray fluorescence micro-analysis for obtaining elemental mapping. In this report, the recent progress on the soft X-ray scanning microscopy and the X-ray microprobe has been surveyed, together with the improvement on the related optical elements. (author) 84 refs

The Model of Gas Supply Capacity Simulation In Regional Energy Security Framework: Policy Studies PT. X Cirebon Area

Science.gov (United States)

Nuryadin; Ronny Rahman Nitibaskara, Tb; Herdiansyah, Herdis; Sari, Ravita

2017-10-01

The needs of energy are increasing every year. The unavailability of energy will cause economic losses and weaken energy security. To overcome the availability of gas supply in the future, planning are cruacially needed. Therefore, it is necessary to approach the system, so that the process of gas distribution is running properly. In this research, system dynamic method will be used to measure how much supply capacity planning is needed until 2050, with parameters of demand in industrial, household and commercial sectors. From the model obtained PT.X Cirebon area in 2031 was not able to meet the needs of gas customers in the Cirebon region, as well as with Businnes as usual scenario, the ratio of gas fulfillment only until 2027. The implementation of the national energy policy that is the use of NRE as government intervention in the model is produced up to 2035 PT.X Cirebon area is still able to supply the gas needs of its customers.

High-resolution bent-crystal spectrometer for the ultra-soft x-ray region

International Nuclear Information System (INIS)

Beiersdorfer, P.; von Goeler, S.; Bitter, M.; Hill, K.W.; Hulse, R.A.; Walling, R.S.

1988-10-01

A multichannel vacuum Brag-crystal spectrometer has been developed for high-resolution measurements of the line emission from tokamak plasmas in the wavelength region between 4 and 25 /angstrom/. The spectrometer employs a bent crystal in Johann geometry and a microchannel-plate intensified photodiode array. The instrument is capable of measuring high-resolution spectra (λ/Δλ ∼ 3000) with fast time resolution (4 msec per spectrum) and good spatial resolution (3 cm). The spectral bandwidth is Δλ/λ 0 = 8/angstrom/. A simple tilt mechanism allows access to different wavelength intervals. In order to illustrate the utility of the new spectrometer, time- and space-resolved measurements of the n = 3 to n = 2 spectrum of selenium from the Princeton Large Torus tokamak plasmas are presented. The data are used to determine the plasma transport parameters and to infer the radial distribution of fluorinelike, neonlike, and sodiumlike ions of selenium in the plasma. The new ultra-soft x-ray spectrometer has thus enabled us to demonstrate the utility of high-resolution L-shell spectroscopy of neonlike ions as a fusion diagnostic. 43 refs., 23 figs

Magnetism and large magnetocaloric effect in HoFe{sub 2-x}Al{sub x}

Energy Technology Data Exchange (ETDEWEB)

Mican, S., E-mail: sever.mican@ubbcluj.ro [Babes-Bolyai University Cluj-Napoca, RO-400084 Cluj-Napoca (Romania); Benea, D., E-mail: diana.benea@phys.ubbcluj.ro [Babes-Bolyai University Cluj-Napoca, RO-400084 Cluj-Napoca (Romania); Tetean, R., E-mail: romulus.tetean@phys.ubbcluj.ro [Babes-Bolyai University Cluj-Napoca, RO-400084 Cluj-Napoca (Romania)

2013-02-05

Highlights: Black-Right-Pointing-Pointer Structural, magnetic and magnetocaloric properties of HoFe{sub 2-x}Al{sub x} compounds are reported. Black-Right-Pointing-Pointer Electronic structure calculations show a good agreement between theory and experiment. Black-Right-Pointing-Pointer Magnetic transitions close to room temperature for the Fe-rich samples. Black-Right-Pointing-Pointer High values of the relative cooling power for all of the investigated samples. Black-Right-Pointing-Pointer No hysteresis losses in applied fields of up to 4 T. - Abstract: The structural, magnetic and magnetocaloric properties of several HoFe{sub 2-x}Al{sub x} compounds were investigated. The compounds in the Fe-rich region (0.36 Less-Than-Or-Slanted-Equal-To x Less-Than-Or-Slanted-Equal-To 0.4) crystallize in the cubic MgCu{sub 2} (C15) structure, while for the ones in the intermediate region (0.75 Less-Than-Or-Slanted-Equal-To x Less-Than-Or-Slanted-Equal-To 1.125) the hexagonal MgZn{sub 2} (C14) structure was observed. Electronic structure calculations were performed, showing a good agreement between theory and experiment. The Curie temperatures were found to decrease with Al content. For the Fe-rich compounds, these are close to room temperature, while for the compounds in the intermediate region, transition temperatures are well below 300 K. No magnetic hysteresis was found around the Curie temperature for applied magnetic fields of up to 4 T. All of the investigated compounds undergo a second-order magnetic phase transition at the Curie temperature. A maximum magnetic entropy change value of 7.6 J/kg K was obtained for the sample with x = 1.125, all of the samples displaying rather large RCP values. The possibility of incorporating these materials in magnetic refrigeration devices is discussed.

Hexagonal perovskites with cationic vacancies. 24. Rhombohedral 9 L stacking polytypes in the systems Ba/sub 3/Wsub(2-x)sup(VI)Msub(x)sup(V)vacantOsub(9-x/2)vacantsub(x/2) with Msup(V) = Nb, Ta

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-12-01

In the system Ba/sub 3/Wsub(2-x)sup(VI)Nbsub(x)sup(V)vacantOsub(9-x/2)vacantsub(x/2) stacking polytypes of rhombohedral 9 L type (sequence (hhc)/sub 3/; space group R-3m) can be prepared with approximately 1/3 <= x <= 2. For x = 2(Ba/sub 3/Nb/sub 2/vacantO/sub 8/vacant) two modifications are formed. In the corresponding Ta system the phase width is reduced to a smaller region with x approximately 1/3.

Assessment of gridded observations used for climate model validation in the Mediterranean region: the HyMeX and MED-CORDEX framework

International Nuclear Information System (INIS)

Flaounas, Emmanouil; Drobinski, Philippe; Borga, Marco; Calvet, Jean-Christophe; Delrieu, Guy; Morin, Efrat; Tartari, Gianni; Toffolon, Roberta

2012-01-01

This letter assesses the quality of temperature and rainfall daily retrievals of the European Climate Assessment and Dataset (ECA and D) with respect to measurements collected locally in various parts of the Euro-Mediterranean region in the framework of the Hydrological Cycle in the Mediterranean Experiment (HyMeX), endorsed by the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Program (WCRP). The ECA and D, among other gridded datasets, is very often used as a reference for model calibration and evaluation. This is for instance the case in the context of the WCRP Coordinated Regional Downscaling Experiment (CORDEX) and its Mediterranean declination MED-CORDEX. This letter quantifies ECA and D dataset uncertainties associated with temperature and precipitation intra-seasonal variability, seasonal distribution and extremes. Our motivation is to help the interpretation of the results when validating or calibrating downscaling models by the ECA and D dataset in the context of regional climate research in the Euro-Mediterranean region. (letter)

Regional differences in political trust: Comparing the Vysocina and Usti Regions

Czech Academy of Sciences Publication Activity Database

Čermák, Daniel; Mikešová, Renáta; Stachová, Jana

2016-01-01

Roč. 49, č. 2 (2016), s. 137-146 ISSN 0967-067X R&D Projects: GA ČR GAP404/12/0714 Institutional support: RVO:68378025 Keywords : Political trust * Regional differences * Czech Republic Subject RIV: AO - Sociology, Demography Impact factor: 0.607, year: 2016 http://www.sciencedirect.com/science/article/pii/S0967067X16300058

X-ray Photoelectron Spectroscopy study of CaV1-xMoxO3-δ

Science.gov (United States)

Belyakov, S. A.; Kuznetsov, M. V.; Shkerin, S. N.

2018-06-01

An investigation was carried out on perovskite-based derivatives of CaV1-xMoxO3-δ using X-ray Photoelectron Spectroscopy (XPS). According to the XRD pattern, the area of homogeneity covers the region from x = 0 to x = 0.6. Wide XPS-peaks of Ca, V, Mo and O are observed, signalling that elements are presented in multiple states. A model for explaining the large chemical shifts of XPS peaks due to different charging effects on different parts of the sample surface is proposed.

Local Conduction in Mo xW1- xSe2: The Role of Stacking Faults, Defects, and Alloying.

Science.gov (United States)

Bampoulis, Pantelis; Sotthewes, Kai; Siekman, Martin H; Zandvliet, Harold J W

2018-04-18

Here, we report on the surface conductivity of WSe 2 and Mo x W 1- x Se 2 (0 ≤ x ≤ 1) crystals investigated with conductive atomic force microscopy. We found that stacking faults, defects, and chemical heterogeneities form distinct two-dimensional and one-dimensional conduction paths on the transition metal dichalcogenide surface. In the case of WSe 2 , in addition to step edges, we find a significant amount of stacking faults (formed during the cleaving process) that strongly influence the surface conductivity. These regions are attributed to the alternation of the 2H and 3R polytypism. The stacking faults form regular 2D patterns by alternation of the underlying stacking order, with a periodicity that varies significantly between different regions and samples. In the case of Mo x W 1- x Se 2 , its conductivity has a localized nature, which depends on the underlying chemical composition and the Mo/W ratio. Segregation to W-rich and Mo-rich regions during the growth process leads to nonuniform conduction paths on the surface of the alloy. We found a gradual change of the conductivity moving from one region to the other, reminiscent of lateral band bending. Our results demonstrate the use of C-AFM as a nanoscopic tool to probe the electrical properties of largely inhomogeneous samples and show the complicated nature of the surface conductivity of TMDC alloys.

The Mapping X-ray Fluorescence Spectrometer (MapX)

Science.gov (United States)

Sarrazin, P.; Blake, D. F.; Marchis, F.; Bristow, T.; Thompson, K.

2017-12-01

Many planetary surface processes leave traces of their actions as features in the size range 10s to 100s of microns. The Mapping X-ray Fluorescence Spectrometer (MapX) will provide elemental imaging at 100 micron spatial resolution, yielding elemental chemistry at a scale where many relict physical, chemical, or biological features can be imaged and interpreted in ancient rocks on planetary bodies and planetesimals. MapX is an arm-based instrument positioned on a rock or regolith with touch sensors. During an analysis, an X-ray source (tube or radioisotope) bombards the sample with X-rays or alpha-particles / gamma-rays, resulting in sample X-ray Fluorescence (XRF). X-rays emitted in the direction of an X-ray sensitive CCD imager pass through a 1:1 focusing lens (X-ray micro-pore Optic (MPO)) that projects a spatially resolved image of the X-rays onto the CCD. The CCD is operated in single photon counting mode so that the energies and positions of individual X-ray photons are recorded. In a single analysis, several thousand frames are both stored and processed in real-time. Higher level data products include single-element maps with a lateral spatial resolution of 100 microns and quantitative XRF spectra from ground- or instrument- selected Regions of Interest (ROI). XRF spectra from ROI are compared with known rock and mineral compositions to extrapolate the data to rock types and putative mineralogies. When applied to airless bodies and implemented with an appropriate radioisotope source for alpha-particle excitation, MapX will be able to analyze biogenic elements C, N, O, P, S, in addition to the cations of the rock-forming elements >Na, accessible with either X-ray or gamma-ray excitation. The MapX concept has been demonstrated with a series of lab-based prototypes and is currently under refinement and TRL maturation.

Features of Microwave Radiation and Magnetographic Characteristics of Solar Active Region NOAA 12242 Before the X1.8 Flare on December 20, 2014

Science.gov (United States)

Abramov-Maximov, V. E.; Borovik, V. N.; Opeikina, L. V.; Tlatov, A. G.; Yasnov, L. V.

2017-12-01

This paper continues the cycle of authors' works on the detection of precursors of large flares (M5 and higher classes) in active regions (ARs) of the Sun by their microwave radiation and magnetographic characteristics. Generalization of the detected precursors of strong flares can be used to develop methods for their prediction. This paper presents an analysis of the development of NOAA AR 12242, in which an X1.8 flare occurred on December 20, 2014. The analysis is based on regular multiazimuth and multiwavelength observations with the RATAN-600 radio telescope in the range 1.65-10 cm with intensity and circular polarization analysis and data from the Solar Dynamics Observatory (SDO). It was found that a new component appeared in the AR microwave radiation two days before the X-flare. It became dominant in the AR the day before the flare and significantly decreased after the flare. The use of multiazimuth observations from RATAN-600 and observations at 1.76 cm from the Nobeyama Radioheliograph made it possible to identify the radio source that appeared before the X-flare with the site of the closest convergence of opposite polarity fields near the neutral line in the AR. It was established that the X-flare occurred 20 h after the total gradient of the magnetic field of the entire region calculated from SDO/HMI data reached its maximum value. Analysis of the evolution of the microwave source that appeared before the X-flare in AR 12242 and comparison of its parameters with the parameters of other components of the AR microwave radiation showed that the new source can be classified as neutral line associated sources (NLSs), which were repeatedly detected by the RATAN-600 and other radio telescopes 1-3 days before the large flares.

Resolution and evolution of the duck-billed platypus karyotype with an X1Y1X2Y2X3Y3X4Y4X5Y5 male sex chromosome constitution.

Science.gov (United States)

Rens, Willem; Grützner, Frank; O'brien, Patricia C M; Fairclough, Helen; Graves, Jennifer A M; Ferguson-Smith, Malcolm A

2004-11-16

The platypus (2n = 52) has a complex karyotype that has been controversial over the last three decades. The presence of unpaired chromosomes and an unknown sex-determining system especially has defied attempts at conventional analysis. This article reports on the preparation of chromosome-specific probes from flow-sorted chromosomes and their application in the identification and classification of all platypus chromosomes. This work reveals that the male karyotype has 21 pairs of chromosomes and 10 unpaired chromosomes (E1-E10), which are linked by short regions of homology to form a multivalent chain in meiosis. The female karyotype differs in that five of these unpaired elements (E1, E3, E5, E7, and E9) are each present in duplicate, whereas the remaining five unpaired elements (E2, E4, E6, E8, and E10) are absent. This finding indicates that sex is determined by the alternate segregation of the chain of 10 during spermatogenesis so that equal numbers of sperm bear either one of the two groups of five elements, i.e., five X and five Y chromosomes. Chromosome painting reveals that these X and Y chromosomes contain pairing (XY shared) and differential (X- or Y-specific) segments. Y differential regions must contain male-determining genes, and X differential regions should be dosage-compensated in the female. Two models for the evolution of the sex-determining system are presented. The resolution of the longstanding debate over the platypus karyotype is an important step toward the understanding of mechanisms of sex determination, dosage compensation, and karyotype evolution.

Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region

Energy Technology Data Exchange (ETDEWEB)

Plogmaker, Stefan; Johansson, Erik M. J.; Rensmo, Haakan; Feifel, Raimund; Siegbahn, Hans [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Linusson, Per [Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Eland, John H. D. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom); Baker, Neville [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom)

2012-01-15

A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of {approx}8 to {approx}120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography.

Science.gov (United States)

Sidky, Emil Y; Kraemer, David N; Roth, Erin G; Ullberg, Christer; Reiser, Ingrid S; Pan, Xiaochuan

2014-10-03

One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data.

Evaluating a Space-Based Indicator of Surface Ozone-NO x -VOC Sensitivity Over Midlatitude Source Regions and Application to Decadal Trends.

Science.gov (United States)

Jin, Xiaomeng; Fiore, Arlene M; Murray, Lee T; Valin, Lukas C; Lamsal, Lok N; Duncan, Bryan; Boersma, K Folkert; De Smedt, Isabelle; Abad, Gonzalo Gonzalez; Chance, Kelly; Tonnesen, Gail S

2017-10-16

Determining effective strategies for mitigating surface ozone (O 3 ) pollution requires knowledge of the relative ambient concentrations of its precursors, NO x , and VOCs. The space-based tropospheric column ratio of formaldehyde to NO 2 (FNR) has been used as an indicator to identify NO x -limited versus NO x -saturated O 3 formation regimes. Quantitative use of this indicator ratio is subject to three major uncertainties: (1) the split between NO x -limited and NO x -saturated conditions may shift in space and time, (2) the ratio of the vertically integrated column may not represent the near-surface environment, and (3) satellite products contain errors. We use the GEOS-Chem global chemical transport model to evaluate the quantitative utility of FNR observed from the Ozone Monitoring Instrument over three northern midlatitude source regions. We find that FNR in the model surface layer is a robust predictor of the simulated near-surface O 3 production regime. Extending this surface-based predictor to a column-based FNR requires accounting for differences in the HCHO and NO 2 vertical profiles. We compare four combinations of two OMI HCHO and NO 2 retrievals with modeled FNR. The spatial and temporal correlations between the modeled and satellite-derived FNR vary with the choice of NO 2 product, while the mean offset depends on the choice of HCHO product. Space-based FNR indicates that the spring transition to NO x -limited regimes has shifted at least a month earlier over major cities (e.g., New York, London, and Seoul) between 2005 and 2015. This increase in NO x sensitivity implies that NO x emission controls will improve O 3 air quality more now than it would have a decade ago.

Making Porous Luminescent Regions In Silicon Wafers

Science.gov (United States)

Fathauer, Robert W.; Jones, Eric W.

1994-01-01

Regions damaged by ion implantation stain-etched. Porous regions within single-crystal silicon wafers fabricated by straightforward stain-etching process. Regions exhibit visible photoluminescence at room temperature and might constitute basis of novel class of optoelectronic devices. Stain-etching process has advantages over recently investigated anodic-etching process. Process works on both n-doped and p-doped silicon wafers. Related development reported in article, "Porous Si(x)Ge(1-x) Layers Within Single Crystals of Si," (NPO-18836).

Unique unbalanced X;X translocation (Xq22;p11.2) in a woman with primary amenorrhea but without Ullrich-Turner syndrome

Energy Technology Data Exchange (ETDEWEB)

Letterie, G.S. [Virginia Mason Medical Center, Seattle, WA (United States)

1995-12-04

This is a report of a patient with delayed puberty and a previously unreported translocation 46,X,-X,+der(X),t(X;X) (q22;p11.2) without any manifestations of Ullrich-Turner syndrome. The relationship of this unbalanced translocation to the critical region hypothesis is discussed. 6 refs., 3 figs.

IGR J17454-2919: a new X-ray transient found by INTEGRAL/JEM-X close to the Galactic Center

DEFF Research Database (Denmark)

Chenevez, Jérôme; Brandt, Søren; Budtz-Jørgensen, Carl

2014-01-01

The JEM-X twin X-ray monitors on board the INTEGRAL satellite have again detected a new X-ray transient during the latest observation of the Galactic Center region. The new source named IGR J17454-2919 is found less than 24 arcmin from the Galactic Center. The source appears in both JEM-X 3-10 ke...

The determination of the surface potential for the CdxHg1-xTe crystals and the V-CdxHg1-xTe and Ni-V-CdxMg1-xTe structures

International Nuclear Information System (INIS)

Veliyulin, Eh.I.; Ragimova, R.A.; Mamedov, A.A.

1996-01-01

Surface potential of semiconductor crystals n-Cd x Hg 1-x Te (unannealed and annealed in mercury vapors) and of the structures V-Cd x Hg 1-x Te, Ni-V-Cd x Hg 1-x Te has been defined using spectroscopy of weak-field electric reflection. It is shown that a deep penetration of vanadium atoms in near the surface region of the crystal occurs in the structures on the basis of unannealed Cd x Hg 1-x Te. 1 ref.; 4 figs

Dental X-ray apparatus

International Nuclear Information System (INIS)

Weiss, M.E.

1980-01-01

Intra-oral dental X-ray apparatus for panoramic radiography is described in detail. It comprises a tubular target carrier supporting at its distal end a target with an inclined forward face. Image definition is improved by positioning in the path of the X-rays a window of X-ray transmitting ceramic material, e.g. 90% oxide of Be, or Al, 7% Si0 2 . The target carrier forms a probe which can be positioned in the patient's mouth. X-rays are directed forwardly and laterally of the target to an X-ray film positioned externally. The probe is provided with a detachable sleeve having V-form arms of X-ray opaque material which serve to depress the tongue out of the radiation path and also shield the roof of the mouth and other regions of the head from the X-ray pattern. A cylindrical lead shield defines the X-ray beam angle. (author)

Mosaicism for r(X and der(Xdel(X(p11.23dup(X(p11.21p11.22 provides insight into the possible mechanism of rearrangement

Directory of Open Access Journals (Sweden)

Fang Ping

2008-07-01

Full Text Available Abstract We report a patient with a unique and complex cytogenetic abnormality involving mosaicism for a small ring X and deleted Xp derivative chromosome with tandem duplication at the break point. The patient presented with failure to thrive, muscular hypotonia, and minor facial anatomic anomalies, all concerning for Turner syndrome. Brain MRI revealed mild thinning of the corpus callosum, an apparent decrease in ventricular white matter volume, and an asymmetric myelination pattern. Array comparative genome hybridization analysis revealed mosaicism for the X chromosome, deletion of the short arm of an X chromosome, and a duplication of chromosome region Xp11.21-p11.22. G-banded chromosome and FISH analyses revealed three abnormal cell lines: 46,X,der(Xdel(X(p11.23dup(X(p11.21p11.22/46,X,r(X(q11.1q13.1/45,X. The small ring X chromosome was estimated to be 5.2 Mb in size and encompassed the centromere and Xq pericentromeric region. X chromosome inactivation (XCI studies demonstrated a skewed pattern suggesting that the ring X remained active, likely contributing to the observed clinical features of brain dysmyelination. We hypothesize that a prezygotic asymmetric crossing over within a loop formed during meiosis in an X chromosome with a paracentric inversion resulted in an intermediate dicentric chromosome. An uneven breakage of the dicentric chromosome in the early postzygotic period might have resulted in the formation of one cell line with the X chromosome carrying a terminal deletion and pericentromeric duplication of the short arm and the second cell line with the X chromosome carrying a complete deletion of Xp. The cell line carrying the deletion of Xp could have then stabilized through self-circularization and formation of the ring X chromosome.

Bridging scale gaps between regional maps of forest aboveground biomass and field sampling plots using TanDEM-X data

Science.gov (United States)

Ni, W.; Zhang, Z.; Sun, G.

2017-12-01

Several large-scale maps of forest AGB have been released [1] [2] [3]. However, these existing global or regional datasets were only approximations based on combining land cover type and representative values instead of measurements of actual forest aboveground biomass or forest heights [4]. Rodríguez-Veiga et al[5] reported obvious discrepancies of existing forest biomass stock maps with in-situ observations in Mexico. One of the biggest challenges to the credibility of these maps comes from the scale gaps between the size of field sampling plots used to develop(or validate) estimation models and the pixel size of these maps and the availability of field sampling plots with sufficient size for the verification of these products [6]. It is time-consuming and labor-intensive to collect sufficient number of field sampling data over the plot size of the same as resolutions of regional maps. The smaller field sampling plots cannot fully represent the spatial heterogeneity of forest stands as shown in Figure 1. Forest AGB is directly determined by forest heights, diameter at breast height (DBH) of each tree, forest density and tree species. What measured in the field sampling are the geometrical characteristics of forest stands including the DBH, tree heights and forest densities. The LiDAR data is considered as the best dataset for the estimation of forest AGB. The main reason is that LiDAR can directly capture geometrical features of forest stands by its range detection capabilities.The remotely sensed dataset, which is capable of direct measurements of forest spatial structures, may serve as a ladder to bridge the scale gaps between the pixel size of regional maps of forest AGB and field sampling plots. Several researches report that TanDEM-X data can be used to characterize the forest spatial structures [7, 8]. In this study, the forest AGB map of northeast China were produced using ALOS/PALSAR data taking TanDEM-X data as a bridges. The TanDEM-X InSAR data used in

Magnetic ordering of Gd/sub x/Er/sub 1-x/Rh4B4 near the superconducting region

International Nuclear Information System (INIS)

Kohn, S.; Wang, R.H.; Smith, J.L.; Huang, C.Y.

1979-01-01

Gd/sub x/Er/sub 1-x/Rh 4 B 4 exhibits superconductivity at some critical temperature T/sub c/ followed by the onset of long-range ferromagnetic ordering at a lower temperature and a loss of superconductivity for x 2 Oe), the extrema in chi (T) and R(T) are depressed and smeared considerably with a corresponding shift in the temperature at which the extrema occur. (2) The sample is not superconducting down to 0.6 K. (3) In the presence of a dc magnetic field, a second ac chi peak appears at a slightly higher temperature. (4) The field dependence of the ac susceptibility resembles that of a spin glass. Details of the field dependence of these observations and the nature of these phenomena will be presented

A molecular dynamics study of the atomic structure of (CaO)x(SiO2)1-x glasses.

Science.gov (United States)

Mead, Robert N; Mountjoy, Gavin

2006-07-27

The local atomic environment of Ca in (CaO)x(SiO2)1-x glasses is of interest because of the role of Ca in soda-lime glass, the application of calcium silicate glasses as biomaterials, and the previous experimental measurement of the Ca-Ca correlation in CaSiO(3) glass. Molecular dynamics has been used to obtain models of (CaO)x(SiO2)1-x glasses with x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5, and with approximately 1000 atoms and size approximately 25 A. As expected, the models contain a tetrahedral silica network, the connectivity of which decreases as x increases. In the glass-forming region, i.e., x = 0.4 and 0.5, Ca has a mixture of 6- and 7-fold coordination. Bridging oxygen makes an important contribution to the coordination of Ca, with most bridging oxygens coordinated to 2 Si plus 1 Ca. The x = 0.5 model is in reasonable agreement with previous experimental studies, and does not substantiate the previous theory of cation ordering, which predicted Ca arranged in sheets. In the phase-separated region, i.e., x = 0.1 and 0.2, there is marked clustering of Ca.

Study of ammonium molecular ion impurity modes in Rb1-x(NH4)xI mixed crystals by inelastic incoherent neutron scattering

International Nuclear Information System (INIS)

Smirnov, L.S.; Natkaniec, I.; Ollivier, J.; Dianoux, J.A.; Martinez Sarrion, M.L.; Mestres, L.

2010-01-01

The study of ammonium dynamics in Rb 1-x (NH 4 ) x I mixed crystals was carried out by inelastic incoherent neutron scattering in the concentration region of orientationally disordered α-phase, 0.0< x<0.40, at the temperature range from 2 to 150 K. The observed resonance modes correspond to three energy regions: 0.19-0.481 (I), 0.56-3.0 (II) and 4.0-10.0 (III) meV. The modes of region I could be described by rotational tunneling energies of the multipole moments of ammonium ions. The modes within energy region II correspond to the calculated rotational tunneling energies between splitted levels of the ground librational level of ammonium ion. The modes of region III can be described as local gap modes of ammonium ion because they are located between acoustic and optic branches of RbI phonon density of states

Sequential evolution of different phases in metastable Gd(2-x)Ce(x)Zr(2-x)Al(x)O7 (0.0 ≤ x ≤ 2.0) system: crucial role of reaction conditions.

Science.gov (United States)

Shukla, Rakesh; Sayed, Farheen N; Phapale, Suhas; Mishra, Ratikant; Tyagi, Avesh K

2013-07-15

The Gd(2-x)Ce(x)Zr(2-x)Al(x)O7 (0.0 ≤ x ≤ 2.0) series was synthesized by the gel combustion method. This system exhibited the presence of a fluorite-type phase, along with a narrow biphasic region, depending upon the Ce/Gd content in the sample. Thermal stability of these new compounds under oxidizing and reducing conditions has been investigated. The products obtained on decomposition of Gd(2-x)Ce(x)Zr(2-x)Al(x)O7 in oxidizing and reducing conditions were found to be entirely different. It was observed that in air the fluorite-type solid solutions of Gd(2-x)Ce(x)Zr(2-x)Al(x)O7 composition undergo phase separation into perovskite GdAlO3 and fluorite-type solid solutions of Gd-Ce-Zr-O or Ce-Zr-Al-O depending upon the extent of Ce and Al substitution. On the other hand, Gd(2-x)Ce(x)Zr(2-x)Al(x)O7 samples on heating under reducing conditions show a phase separation to CeAlO3 perovskite and a defect-fluorite of Gd2Zr2O7. The extent of metastability for a typical composition of Gd(1.2)Ce(0.8)Zr(1.2)Al(0.8)O7 (nano), Gd(1.2)Ce(0.8)Zr(1.2)Al(0.8)O(6.6) (heated under reduced conditions), Gd(1.2)Ce(0.8)Zr(1.2)Al(0.8)O7 (heated in air at 1200 °C) has been experimentally determined employing a high temperature Calvet calorimeter. On the basis of thermodynamic stability data, it could be inferred that the formation of a more stable compound in the presence of two competing cations (i.e., Gd(3+) and Ce(3+)) is guided by the crystallographic stability.

A new X-ray transient, IGR J17451-3022, discovered by INTEGRAL/JEM-X near the Galactic Centre

DEFF Research Database (Denmark)

Chenevez, Jérôme; Vandbaek Kroer, L.; Budtz-Jørgensen, Carl

2014-01-01

The JEM-X twin X-ray monitors on board the INTEGRAL satellite has detected a new X-ray transient during recent observations of the Galactic Centre and Bulge regions. The new source named IGR J17451-3022 has the following coordinates: R.A. = 266.27 Dec. = -30.38 with a 2arcmin 90% confidence radiu...

Linear polarization observations of some X-ray sources

International Nuclear Information System (INIS)

Shakhovskoy, N.M.; Efimov, Yu.S.

1975-01-01

Multicolour linear polarization of optical radiation of the X-ray sources Sco X-1, Cyg X-2, Cyg X-1 and Her X-1 was measured at the Crimean Astrophysical Observatory in 1970-1973. These observations indicate that polarization of Sco X-1 in the ultraviolet, blue and red spectral regions appears to be variable. No statistically significant variations of polarization were found for the other three sources observed. (Auth.)

Duodenal X-ray diagnostics

International Nuclear Information System (INIS)

Scheppach, W.

1982-01-01

The publication provides an overview of duodenal X-ray diagnostics with the aid of barium meals in 1362 patients. The introducing paragraphs deal with the topographic anatomy of the region and the methodics of X-ray investigation. The chapter entitled ''processes at the duodenum itself'' describes mainly ulcers, diverticula, congenital anomalies, tumors and inflammations. The neighbourhood processes comprise in the first place diseases having their origin at the pancreas and bile ducts. As a conclusion, endoscopic rectograde cholangio-pancreaticography and percutaneous transhepatic cholangiography are pointed out as advanced X-ray investigation methods. In the annex of X-ray images some of the described phenomena are shown in exemplary manner. (orig./MG) [de

Small-x physics at LEP/LHC

International Nuclear Information System (INIS)

Bartels, J.; Schuler, G.A.

1990-12-01

The small-x behavior of deep inelastic structure functions in QCD is discussed. After a brief review of theoretical ideas we describe numerical estimates which show that LEP/LHC will be extremely useful for distinguishing between 'standard QCD' and 'new' physics in the low-x region. We also discuss which measurements will be useful for unravelling the new features of small-x physics. (orig.)

Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography

Science.gov (United States)

Sidky, Emil Y.; Kraemer, David N.; Roth, Erin G.; Ullberg, Christer; Reiser, Ingrid S.; Pan, Xiaochuan

2014-01-01

Abstract. One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data. PMID:25685824

Cooling Active Region Loops Observed With SXT and TRACE

OpenAIRE

Winebarger, Amy R.; Warren, Harry P.

2005-01-01

An Impulsive Heating Multiple Strand (IHMS) Model is able to reproduce the observational characteristics of EUV (~ 1 MK) active region loops. This model implies that some of the loops must reach temperatures where X-ray filters are sensitive (> 2.5 MK) before they cool to EUV temperatures. Hence, some bright EUV loops must be preceded by bright X-ray loops. Previous analysis of X-ray and EUV active region observations, however, have concluded that EUV loops are not preceded by X-ray loops. In...

Transition from weak ferromagnetism to metamagnetism in the itinerant-electron system Y{sub 1-x}La{sub x}Co{sub 9}Si{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, M; Kohara, T [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan); Nakamura, H [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan)

2010-01-15

The magnetism of solid solution Yi{sub 1-x}La{sub x}Co{sub 9}Si{sub 4} between strongly enhanced Pauli paramagnetic LaCo{sub 9}Si{sub 4} and weakly ferromagnetic YCo{sub 9}Si{sub 4} has been investigated. The Curie temperature T{sub C} in the ferromagnetic region and the metamagnetic transition field H{sub M} in the paramagnetic region change continuously against x and approach zero at the same composition x {approx_equal} 0.15, suggesting the presence of a critical point from spontaneous to field-induced ferromagnetism.

HOT PLASMA FROM SOLAR ACTIVE-REGION CORES: CONSTRAINTS FROM THE HINODE X-RAY TELESCOPE

Energy Technology Data Exchange (ETDEWEB)

Schmelz, J. T. [USRA, 7178 Columbia Gateway Drive, Columbia, MD 21046 (United States); Christian, G. M.; Matheny, P. O., E-mail: jschmelz@usra.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

2016-12-20

Mechanisms invoked to heat the solar corona to millions of degrees kelvin involve either magnetic waves or magnetic reconnections. Turbulence in the convection zone produces MHD waves, which travel upward and dissipate. Photospheric motions continuously build up magnetic energy, which is released through magnetic reconnection. In this paper, we concentrate on hot non-flaring plasma with temperatures of 5 MK <  T  < 10 MK because it is one of the few observables for which wave and reconnection models make different predictions. Wave models predict no (or little) hot plasma, whereas reconnection models predict it, although in amounts that are challenging to detect with current instrumentation. We used data from the X-ray Telescope (XRT) and the Atmospheric Imaging Assembly (AIA). We requested a special XRT observing sequence, which cycled through the thickest XRT filter several times per hour so we could average these images and improve the signal-to-noise. We did differential emission measure (DEM) analysis using the time-averaged thick-filter data as well as all available channels from both the XRT and AIA for regions observed on 2014 December 11. Whereas our earlier work was only able to determine that plasma with a temperature greater than 5 MK was present , we are now able to find a well-constrained DEM distribution. We have therefore added a strong observational constraint that must be explained by any viable coronal heating model. Comparing state-of-the-art wave and reconnection model predictions, we can conclude that reconnection is heating the hot plasma in these active regions.

Radiometer evaluation of X-rays equipment in the region of Aracatuba, Sao Paulo, Brazil;Avaliacao radiometrica de raios-X na regiao de Aracatuba, Sao Paulo

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Marco A.R. [UNESP, Botucatu, SP (Brazil). Faculdade de Medicina; Kanezawa, Jorge S. [Centro de Ensino e Tecnologia de Aracatuba (CETEA), SP (Brazil)

2009-07-01

This paper presents the basic concepts of radiation protection to guide the health care professionals who use equipment emitting ionizing radiation on the correct handling of the beams of radiation. Radiometric evaluations were conducted in 1665 in X-ray equipment, installed in dental surgeries and clinics, hospitals and radiology services, during the years 1996 to 2003 in the region of Aracatuba. Tests of radiometry are presented as a technical report where the parameters are quantified physical and radiological verifying its compliance with the established by legislation. The distribution of reports by type of unit shows that the vast majority of equipment is of periapical dental x-rays (72%), 25% of equipment is medical equipment for radiology and 3% is dental equipment panoramic model (orthodontic documentation). Among the physical parameters analyzed, the length of the browser was showing more variance compared to the required by law, this fact may also contribute to gaps in the rate of the radiation dose and the size of field in the skin of the patient, the that can easily be resolved simply to replace the piece at the outlet of the head. During the completion of visits to services, it also noted a gap in the training of professionals who operate this equipment emitting radiation, warning of the need for specific training in the area. (author)

Triggering Process of the X1.0 Three-ribbon Flare in the Great Active Region NOAA 12192

Energy Technology Data Exchange (ETDEWEB)

Bamba, Yumi [Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA) 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Inoue, Satoshi; Kusano, Kanya; Shiota, Daikou, E-mail: y-bamba@nagoya-u.jp [Institute for Space-Earth Environmental Research (ISEE)/Nagoya University Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)

2017-04-01

The solar magnetic field in a flare-producing active region (AR) is much more complicated than theoretical models, which assume a very simple magnetic field structure. The X1.0 flare, which occurred in AR 12192 on 2014 October 25, showed a complicated three-ribbon structure. To clarify the trigger process of the flare and to evaluate the applicability of a simple theoretical model, we analyzed the data from Hinode /Solar Optical Telescope and the Solar Dynamics Observatory /Helioseismic and Magnetic Imager, Atmospheric Imaging Assembly. We investigated the spatio-temporal correlation between the magnetic field structures, especially the non-potentiality of the horizontal field, and the bright structures in the solar atmosphere. As a result, we determined that the western side of the positive polarity, which is intruding on a negative polarity region, is the location where the flare was triggered. This is due to the fact that the sign of the magnetic shear in that region was opposite that of the major shear of the AR, and the significant brightenings were observed over the polarity inversion line (PIL) in that region before flare onset. These features are consistent with the recently proposed flare-trigger model that suggests that small reversed shear (RS) magnetic disturbances can trigger solar flares. Moreover, we found that the RS field was located slightly off the flaring PIL, contrary to the theoretical prediction. We discuss the possibility of an extension of the RS model based on an extra numerical simulation. Our result suggests that the RS field has a certain flexibility for displacement from a highly sheared PIL, and that the RS field triggers more flares than we expected.

Absorption of X-rays in the interstellar medium

International Nuclear Information System (INIS)

Ride, S.K.; Stanford Univ., Calif.; Walker, A.B.C. Jr.; Stanford Univ., Calif.

1977-01-01

In order to interpret soft X-ray spectra of cosmic X-ray sources, it is necessary to know the photoabsorption cross-section of the intervening interstellar material. Current models suggest that the interstellar medium contains two phases which make a substantial contribution to the X-ray opacity: cool, relatively dense clouds that exist in pressure equilibrium with hot, tenuous intercloud regions. We have computed the soft X-ray photoabsorption cross-section (per hydrogen atom) of each of these two phases. The calculation are based on a model of the interstellar medium which includes chemical evolution of the galaxy, the formation of molecules and grains, and the ionization structure of each of each phase. These cross-sections of clouds and of intercloud regions can be combined to yield the total soft X-ray photoabsorption cross-section of the interstellar medium. By choosing the appropriate linear combination of cloud and intercloud cross-sections, we can tailor the total cross-section to a particular line-of-sight. This approach, coupled with our interstellar model, enables us to better describe a wide range of interstellar features such as H II regions, dense (molecular) clouds, or the ionized clouds which may surround binary X-ray sources. (orig.) [de

X-prolyl dipeptidyl aminopeptidase gene (pepX) is part of the glnRA operon in Lactobacillus rhamnosus.

Science.gov (United States)

Varmanen, P; Savijoki, K; Avall, S; Palva, A; Tynkkynen, S

2000-01-01

A peptidase gene expressing X-prolyl dipeptidyl aminopeptidase (PepX) activity was cloned from Lactobacillus rhamnosus 1/6 by using the chromogenic substrate L-glycyl-L-prolyl-beta-naphthylamide for screening of a genomic library in Escherichia coli. The nucleotide sequence of a 3.5-kb HindIII fragment expressing the peptidase activity revealed one complete open reading frame (ORF) of 2,391 nucleotides. The 797-amino-acid protein encoded by this ORF was shown to be 40, 39, and 36% identical with PepXs from Lactobacillus helveticus, Lactobacillus delbrueckii, and Lactococcus lactis, respectively. By Northern analysis with a pepX-specific probe, transcripts of 4.5 and 7.0 kb were detected, indicating that pepX is part of a polycistronic operon in L. rhamnosus. Cloning and sequencing of the upstream region of pepX revealed the presence of two ORFs of 360 and 1,338 bp that were shown to be able to encode proteins with high homology to GlnR and GlnA proteins, respectively. By multiple primer extension analyses, the only functional promoter in the pepX region was located 25 nucleotides upstream of glnR. Northern analysis with glnA- and pepX-specific probes indicated that transcription from glnR promoter results in a 2.0-kb dicistronic glnR-glnA transcript and also in a longer read-through polycistronic transcript of 7.0 kb that was detected with both probes in samples from cells in exponential growth phase. The glnA gene was disrupted by a single-crossover recombinant event using a nonreplicative plasmid carrying an internal part of glnA. In the disruption mutant, glnRA-specific transcription was derepressed 10-fold compared to the wild type, but the 7.0-kb transcript was no longer detectable with either the glnA- or pepX-specific probe, demonstrating that pepX is indeed part of glnRA operon in L. rhamnosus. Reverse transcription-PCR analysis further supported this operon structure. An extended stem-loop structure was identified immediately upstream of pepX in the glnA-pepX

Shielding of the abdominal region during X-irradiation: Effect on haemopoietic stem cells

International Nuclear Information System (INIS)

Vavrova, J.; Petyrek, P.

1984-01-01

The shielding of the abdominal region during X-irradiation is important for two reasons: 1) it prevents the development of the gastrointestinal syndrome following higher radiation doses; 2) it prevents the development of the lethal form of the bone marrow syndrome by shielding a portion of the spinal column bone marrow and the spleen. The dose reduction factor in partial irradiated mice compared to whole-body irradiated mice was 2.6. 15 mins after irradiation with the dose of 10 Gy, the number of spleen colony-forming cells (CFU-S) decreased in the femoral bone marrow of both the group receiving whole-body irradiation and the group having the abdominal region shielded. This decrease persisted in both groups for five hours after irradiation. 48 hours after whole-body irradiation, the number of CFU-S in the femoral bone marrow of the unshielded animals decreased almost to zero values. In shielded group, a statistically significant increase in the number of CFU-S in the femur was observed at 48 hours. At 120 hours, the number of CFU-S in so irradiated mice was at the level of the unirradiated group. In the spleen a great decrease in the number of CFU-S was caused by whole-body irradiation of mice as early as 15 mins after irradiation and the low-levels were recorded until the death of animals. In the shielded group, a statistically signifjcant decrease in the number of CFU-S was observed 15 mins after irradiation, which may have been due to the abscopal effect of irradiation. After a transient recovery 2 hours after irradiation, a significant decrease in the number of CFU-S in the spleens was observed in the subsequent interval from five to 120 hours after irradiation. (author)

Sensitivities of JEM-X

DEFF Research Database (Denmark)

Westergaard, Niels Jørgen Stenfeldt; Lund, Niels

1999-01-01

The mask design for JEM-X is now finalized regarding the hole pattern and mechnical support structure. The engineering model of the detectors with collimators is under construction. The JEM-X sensitivities for source detection in various circumstances are reviewed with proper regard to the way...... INTEGRAL will carry out its pointed observations. An important fraction of the INTEGRAL observation time will be used for scans along the galactic plane and observations of the central region of our galaxy. The JEM-X performance for this type of observations is discussed. The software tools used to carry...

How Resummation Depresses the Gluon at Small x

CERN Document Server

Forte, Stefano; Ball, Richard D.; Forte, Stefano; Altarelli, Guido; Ball, Richard D.

2006-01-01

We summarize recent progress in the resummation of perturbative evolution at small x. We show that the problem of incorporating BFKL small x logs in GLAP evolution is now completely solved, and that the main effect of small x resummation is to reduce the growth of the gluon at small x in the HERA and LHC regions.

QCD coherence in the structure function and associated distributions at small x

International Nuclear Information System (INIS)

Marchesini, G.

1995-01-01

We recall the origin of angular ordering in soft parton emission and show that at small x this coherent structure is masked in the structure function while it can be detected in the associated distributions. This is due to the fact that collinear singularities cancel completely in the structure function at fixed transverse momentum for x →0. In this limit the dependence on the hard scale is lost, the angular ordered region becomes equivalent to the multi-Regge region in which all transverse momenta are of the same order, and one derives the BFKL equation. For the associated distributions at small x such a complete cancellation of collinear singularities does not hold in general, thus large singular contributions are neglected if angular ordering is replaced by multi-Regge phase space. The deduction of these features requires an analysis without any collinear approximations which is done by extending to small x the soft gluon factorization techniques typically used in the region of large x. Since the coherent structure of parton emission is the same in the small and large x regions, one can formulate a unified evolution equation for the structure function, a unified coherent branching and jet algorithm which allows the calculation of associated distributions in all x regions. Such a unified formulation, valid for all x, is presented and compared with usual treatments. ((orig.))

Neutron scattering study of La1-xCaxMnO3 with x=0.15

International Nuclear Information System (INIS)

Begum, Shahnaz; Ono, Yasuhiro; Miyazaki, Yuzuru; Kajitani, Tsuyoshi; Tomioka, Yasuhide; Tokura, Yoshinori

2001-01-01

Elastic and inelastic neutron scattering measurements have been made on a perovskite hole doped manganite La 1-x Ca x MnO 3 with x=0.15 for both powder and single crystal samples to understand the magnetic properties of this compound. Strong diffuse scattering observed in the paramagnetic phase, originates from the ferromagnetic spin fluctuations. New peaks have been observed at 001, 100 and 1/2 0 1/2 from 15 K to the ambient temperature indicating the long-range and/or short-range charge and magnetic spin ordering. An anomalous temperature dependent inelastic scattering intensities were observed by the TOF neutron spectrometer AGNES at 2θ=57-64deg (close to 101 Bragg peak) at temperatures from 17 to 220 K for powder sample. The peak at about 1.0 meV was only observed at 17 and 98 K in the ferromagnetic region and smeared in the paramagnetic region which is possibly the indication of spin gap formation in the ferromagnetic region. The peak at about 1.0 meV at lower temperatures were also observed for single crystal sample close to 1/2 0 1/2 reciprocal point. (author)

Phase relations, crystal structure, and phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) in In_2O_3–Nb_2O_5–TiO_2 system

International Nuclear Information System (INIS)

Su, Liumei; Fan, Xing; Cai, Gemei; Liu, Huashan; Jin, Zhanpeng

2015-01-01

Phase relations, crystal structures, and phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) in In_2O_3–Nb_2O_5–TiO_2 ternary system were investigated for the first time. A number of samples with different compositions were prepared by a solid-state reaction method, and phase assembles were analyzed by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe micro-analysis (EPMA). Five three-phase regions, ten two-phase regions, and six single-phase solid solutions were determined in this system. The solid solution of In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) is composed of both ordered monoclinic wolframite-type structure (0 ≤ x < 0.35) and disordered orthorhombic α-PbO_2 type structure (0.35 < x < 0.45). Driving force for composition-driven phase transformation in In_1_−_xNb_1_−_xTi_2_xO_4 (0 ≤ x < 0.45) stems from the ordering of cations. The ever reported compound InNbTiO_6 with an orthorhombic α-PbO_2 type structure was amended to be a monoclinic wolframite-type structure. Present investigations will be useful for the whole ceramic community working with In_2O_3–Nb_2O_5–TiO_2 ternary system as well as for the development of functional materials. - Highlights: • Phase relations of In_2O_3–Nb_2O_5–TiO_2 ternary system were constructed. • Crystal structures of a novel solid solution In_1_−_xNb_1_−_xTi_2_xO_4 were determined. • Crystal structure of InNbTiO_6 was amended to be a wolframite-type structure. • Composition-driven phase transformation of In_1_−_xNb_1_−_xTi_2_xO_4 was investigated.

Helicity dependence of the γ 3He → πX reactions in the Δ(1232) resonance region

International Nuclear Information System (INIS)

Costanza, S.; Rigamonti, F.; Mushkarenkov, A.; Braghieri, A.; Pedroni, P.; Romaniuk, M.; Mandaglio, G.; Aguar Bartolome, P.; Ahrens, J.; Arends, H.J.; Heid, E.; Jahn, O.; Kashevarov, V.L.; Ostrick, M.; Ortega, H.; Otte, P.B.; Oussena, B.; Schumann, S.; Thomas, A.; Unverzagt, M.; Annand, J.R.M.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; Rosner, G.; Beck, R.; Bekrenev, V.; Kruglov, S.; Kulbardis, A.; Berghaeuser, H.; Drexler, P.; Metag, V.; Thiel, M.; Briscoe, W.J.; Downie, E.J.; Cherepnya, S.N.; Fil'kov, L.V.; Lisin, V.; Polonski, A.; Collicott, C.; Fix, A.; Glazier, D.I.; Heil, W.; Krimmer, J.; Hornidge, D.; Middleton, D.G.; Jaegle, I.; Keshelashvili, I.; Krusche, B.; Oberle, M.; Pheron, F.; Rostomyan, T.; Werthmueller, D.; Huber, G.M.; Jude, T.; Watts, D.P.; Kondratiev, R.; Korolija, M.; Supek, I.; Manley, D.M.; Nefkens, B.M.K.; Starostin, A.; Nikolaev, A.; Prakhov, S.; Sarty, A.J.

2014-01-01

The helicity dependences of the differential cross sections for the semi-inclusive γ 3 He → π 0 X and γ 3 He → π ± X reactions have been measured for the first time in the energy region 200 γ 450 MeV. The experiment was performed at the tagged photon beam facility of the MAMI accelerator in Mainz using a longitudinally polarised high-pressure 3 He gas target. Hadronic products were measured with the large-acceptance Crystal Ball detector complemented with additional devices for charged-particle tracking and identification. Unpolarised differential cross sections and their helicity dependence are compared with theoretical calculations using the Fix-Arenhoevel model. The effect of the intermediate excitation of the Δ(1232) resonance can be clearly seen from this comparison, especially for the polarised case, where nuclear effects are relatively small. The model provides a better theoretical description of the unpolarised charged pion photoproduction data than the neutral pion channel. It does significantly better in describing the helicity-dependent data in both channels. These comparisons provide new information on the mechanisms involved in pion photoproduction on 3 He and suggest that a polarised 3 He target can provide valuable information on the corresponding polarised quasi-free neutron reactions. (orig.)

Flavor singlet contribution to the structure function g1 at small-x

International Nuclear Information System (INIS)

Bartels, J.; Ryskin, M.G.

1996-02-01

The singlet contribution to the g 1 (x, Q 2 ) structure function are calculated in the double-logarithmic approximation of perturbative QCD in the region x s ln 2 (1/x)) k which are not included in the GLAP evolution equations are shown to give a power-like rise at small-x which is much stronger than the extrapolation of the GLAP expressions. The dominant contribution is due to the gluons which, in contrast to the unpolarized case, mix with the fermions also in the region x<<1. The two main reasons why the small-x behavior of the double logarithmic approximation is so much stronger than the usual GLAP evolution are: the larger kinematical region of integration (in particular, no ordering in transverse momentum) and the contributions from non-ladder diagrams. (orig.)

An X-point ergodic divertor

International Nuclear Information System (INIS)

Chu, M.S.; Jensen, T.H.; La Haye, R.J.; Taylor, T.S.; Evans, T.E.

1991-10-01

A new ergodic divertor is proposed. It utilizes a system of external (n = 3) coils arranged to generate overlapping magnetic islands in the edge region of a diverted tokamak and connect the randomized field lines to the external (cold) divertor plate. The novel feature in the configuration is the placement of the external coils close to the X-point. A realistic design of the external coil set is studied by using the field line tracing method for a low aspect ratio (A ≅ 3) tokamak. Two types of effects are observed. First, by placing the coils close to the X-point, where the poloidal magnetic field is weak and the rational surfaces are closely packed only a moderate amount of current in the external coils is needed to ergodize the edge region. This ergodized edge enhances the edge transport in the X-point region and leads to the potential of edge profile control and the avoidance of edge localized modes (ELMs). Furthermore, the trajectories of the field lines close to the X-point are modified by the external coil set, causing the hit points on the external divertor plates to be randomized and spread out in the major radius direction. A time-dependent modulation of the currents in the external (n = 3) coils can potentially spread the heat flux more uniformly on the divertor plate avoiding high concentration of the heat flux. 10 refs., 9 figs

Temporal behavior of unresolved transition array emission in water window soft x-ray spectral region from multiply charged ions

Energy Technology Data Exchange (ETDEWEB)

Dinh, Thanh-Hung, E-mail: dinh@cc.utsunomiya-u.ac.jp; Suzuki, Yuhei; Arai, Goki; Higashiguchi, Takeshi, E-mail: higashi@cc.utsunomiya-u.ac.jp [Department of Electrical and Electronic Engineering, Faculty of Engineering and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Li, Bowen [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Dunne, Padraig; O' Sullivan, Gerry [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Fujioka, Shinsuke [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Hasegawa, Noboru; Kawachi, Tetsuya; Nishikino, Masaharu [Quantum Beam Science Center, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)

2015-09-21

We have characterized the spectral structure and the temporal history of the laser-produced high-Z multi-charged ion plasmas for the efficient water window soft x-ray sources. Strong unresolved transition array emission was observed due to 4d–4f and 4f–5g transitions from Au, Pb, and Bi plasmas in the 280–700 eV photon energy region. The temporal behavior of the emission was essentially similar of that of the laser pulse with a slight delay between different transitions. These results provide feedback for accurate modeling of the atomic processes with the radiative hydrodynamic simulations.

Purification, crystallization and preliminary X-ray diffraction analysis of the Kelch-like motif region of mouse Keap1

Energy Technology Data Exchange (ETDEWEB)

Padmanabhan, Balasundaram; Scharlock, Maria [RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045 (Japan); Tong, Kit I. [Graduate School of Comprehensive Human Sciences, Center for Tsukuba Advanced Research Alliance and ERATO Environmental Research Project, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577 (Japan); Nakamura, Yoshihiro [RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045 (Japan); Kang, Moon-Il; Kobayashi, Akira [Graduate School of Comprehensive Human Sciences, Center for Tsukuba Advanced Research Alliance and ERATO Environmental Research Project, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577 (Japan); Matsumoto, Takehisa; Tanaka, Akiko [RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045 (Japan); Yamamoto, Masayuki [Graduate School of Comprehensive Human Sciences, Center for Tsukuba Advanced Research Alliance and ERATO Environmental Research Project, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577 (Japan); Yokoyama, Shigeyuki, E-mail: yokoyama@biochem.s.u-tokyo.ac.jp [RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045 (Japan); Cellular Signaling Laboratory and Structurome Research Group, RIKEN Harima Institute at SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo, Hyogo 679-5148 (Japan); Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2005-01-01

Keap1-DC (Kelch/double-glycine repeat and C-terminal region) of mouse Keap1 has been overexpressed in E. coli, purified and crystallized using the vapour-diffusion method. Keap1 (Kelch-like ECH-associating protein 1) is a negative regulator of the Nrf2 transcription factor in the cytoplasm. The Kelch/DGR (double-glycine repeat) domain of Keap1 associates with Nrf2 as well as with actin filaments. A recombinant protein containing both the Kelch/DGR domain and the C-terminal region of mouse Keap1 was expressed in Escherichia coli, purified to near-homogeneity and crystallized by the sitting-drop vapour-diffusion method. The crystal belongs to space group P6{sub 1} or P6{sub 5}, with unit-cell parameters a = b = 102.95, c = 55.21 Å, and contains one molecule in the asymmetric unit. A complete diffraction data was collected to 2.25 Å resolution using an R-AXIS IV{sup ++} imaging plate mounted on an RA-Micro7 Cu Kα rotating-anode X-ray generator.

Anisotropic response of the moving vortex lattice in superconducting Mo{sub (1-x)}Ge{sub x} amorphous films

Energy Technology Data Exchange (ETDEWEB)

Dolz, M.I., E-mail: mdolz@unsl.edu.ar [Centro Atomico Bariloche, CONICET, San Carlos de Bariloche, R8402AGP Rio Negro (Argentina); Shalom, D.E.; Pastoriza, H. [Centro Atomico Bariloche, CONICET, San Carlos de Bariloche, R8402AGP Rio Negro (Argentina); Lopez, D.O. [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Av., Argonne, IL 60439 (United States)

2012-03-15

We have performed magnetic susceptibility measurements in Mo{sub 1-x}Ge{sub x} amorphous thin films biased with an electrical current using anisotropic coils. We tested the symmetry of the vortex response changing the relative orientation between the bias current and the susceptibility coils. We found a region in the DC current-temperature phase diagram where the dynamical vortex structures behave anisotropically. In this region the shielding capability of the superconducting currents measured by the susceptibility coils is less effective along the direction of vortex motion compared to the transverse direction. This anisotropic response is found in the same region where the peak effect in the critical current is developed. On rising temperature the isotropic behavior is recovered.

Automated selection of trabecular bone regions in knee radiographs

International Nuclear Information System (INIS)

Podsiadlo, P.; Wolski, M.; Stachowiak, G. W.

2008-01-01

Osteoarthritic (OA) changes in knee joints can be assessed by analyzing the structure of trabecular bone (TB) in the tibia. This analysis is performed on TB regions selected manually by a human operator on x-ray images. Manual selection is time-consuming, tedious, and expensive. Even if a radiologist expert or highly trained person is available to select regions, high inter- and intraobserver variabilities are still possible. A fully automated image segmentation method was, therefore, developed to select the bone regions for numerical analyses of changes in bone structures. The newly developed method consists of image preprocessing, delineation of cortical bone plates (active shape model), and location of regions of interest (ROI). The method was trained on an independent set of 40 x-ray images. Automatically selected regions were compared to the ''gold standard'' that contains ROIs selected manually by a radiologist expert on 132 x-ray images. All images were acquired from subjects locked in a standardized standing position using a radiography rig. The size of each ROI is 12.8x12.8 mm. The automated method results showed a good agreement with the gold standard [similarity index (SI)=0.83 (medial) and 0.81 (lateral) and the offset=[-1.78, 1.27]x[-0.65,0.26] mm (medial) and [-2.15, 1.59]x[-0.58, 0.52] mm (lateral)]. Bland and Altman plots were constructed for fractal signatures, and changes of fractal dimensions (FD) to region offsets calculated between the gold standard and automatically selected regions were calculated. The plots showed a random scatter and the 95% confidence intervals were (-0.006, 0.008) and (-0.001, 0.011). The changes of FDs to region offsets were less than 0.035. Previous studies showed that differences in FDs between non-OA and OA bone regions were greater than 0.05. ROIs were also selected by a second radiologist and then evaluated. Results indicated that the newly developed method could replace a human operator and produces bone regions

The GlueX DIRC detector

Science.gov (United States)

Barbosa, F.; Bessuille, J.; Chudakov, E.; Dzhygadlo, R.; Fanelli, C.; Frye, J.; Hardin, J.; Kelsey, J.; Patsyuk, M.; Schwarz, C.; Schwiening, J.; Stevens, J.; Shepherd, M.; Whitlatch, T.; Williams, M.

2017-12-01

The GlueX DIRC (Detection of Internally Reflected Cherenkov light) detector is being developed to upgrade the particle identification capabilities in the forward region of the GlueX experiment at Jefferson Lab. The GlueX DIRC will utilize four existing decommissioned BaBar DIRC bar boxes, which will be oriented to form a plane roughly 4 m away from the fixed target of the experiment. A new photon camera has been designed that is based on the SuperB FDIRC prototype. The full GlueX DIRC system will consist of two such cameras, with the first planned to be built and installed in 2017. We present the current status of the design and R&D, along with the future plans of the GlueX DIRC detector.

Grain boundary tunnel spectroscopy of the electron-doped cuprate superconductor La{sub 2-x}Ce{sub x}CuO{sub 4}; Korngrenzen-Tunnelspektroskopie am elektronendotierten Kupratsupraleiter La{sub 2-x}Ce{sub x}CuO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Wagenknecht, Michael

2008-07-01

The electron doped superconductor La{sub 2-x}Ce{sub x}CuO{sub 4} (LCCO) has been investigated by electric transport measurements at low temperatures T down to 5 K and high magnetic fields up to 16 T. For this purpose LCCO thin film tunnel junctions have been prepared on bicrystal substrates by molecular beam epitaxy and micro structuring. The samples were characterised by measuring the thin film resistivity and the tunnel conductance of quasi particles across the grain boundary. By these measurements an unconventional symmetry of the order parameter could be revealed for La{sub 2-x}Ce{sub x}CuO{sub 4}. Furthermore it was shown, that the tunnel conductance can be used as a probe for the upper critical field B{sub c2}(T). By using this method a value of B{sub c2}{proportional_to}24 T has been found for La{sub 2-x}Ce{sub x}CuO{sub 4}, a value roughly three times bigger than previously known. By this observation it was shown that the superconducting phase covers a larger region in the B-T-phase diagram. In addition it was concluded, that the pseudogap phase in La{sub 2-x}Ce{sub x}CuO{sub 4} is either not existent at all or covers only a small temperature region. Besides quasiparticle tunneling also the tunneling of Cooper pairs in small magnetic fields has been investigated. It was shown that the critical current across the grain boundary depends on the supplier of the bicrystal substrate. (orig.)

Signatures of Synchrotron: Low-cutoff X-ray emission and the hard X-ray spectrum of Cas A

Science.gov (United States)

Stage, Michael D.; Fedor, Emily Elizabeth; Martina-Hood, Hyourin

2018-06-01

In soft X-rays, bright, young Galactic remnants (Cas A, Kepler, Tycho, etc.) present thermal line emission and bremsstrahlung from ejecta, and synchrotron radiation from the shocks. Their hard X-ray spectra tend to be dominated by power-law sources. However, it can be non-trivial to discriminate between contributions from processes such as synchrotron and bremsstrahlung from nonthermally accelerated electrons, even though the energies of the electrons producing this radiation may be very different. Spatially-resolved spectroscopic analysis of 0.5-10 keV observations with, e.g., Chandracan provide leverage in identifying the processes and their locations. Previously, Stage & Allen (2006), Allen & Stage (2007) and Stage & Allen (2011) identified regions characterized by high-cutoff synchrotron radiation. Extrapolating synchrotron model fits to the emission in the Chandra band, they estimated the synchrotron contribution to the hard X-ray spectrum at about one-third the observed flux, fitting the balance with nonthermal bremsstrahlung emission produced by nonthermal electrons in the ejecta. Although it is unlikely this analysis missed regions of the highest-cutoff synchrotron emission, which supplies the bulk of the synchrotron above 15 keV, it may have missed regions of lower-cutoff emission, especially if they are near bright ejecta and the reverse shock. These regions cannot explain the emission at the highest energies (~50 keV), but may make significant contributions to the hard spectrum at lower energies (~10 keV). Using the technique described in Fedor, Martina-Hood & Stage (this meeting), we revisit the analysis to include regions that may be dominated by low-cutoff synchrotron, located in the interior of the remnant, and/or correlated with the reverse shock. Identifying X-ray emission from accelerated electrons associated with the reverse-shock would have important implications for synchrotron and non-thermal bremsstrahlung radiation above the 10 keV.

NuSTAR Hard X-ray Survey of the Galactic Center Region. I. Hard X-ray Morphology and Spectroscopy of the Diffuse Emission

DEFF Research Database (Denmark)

Mori, Kaya; Hailey, Charles J.; Krivonos, Roman

2015-01-01

We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456-2901 into non-thermal X-ray filaments, molecular clouds, point sources, and a previously unknown central component of hard X-ray emission (CHXE). Nu...

Gamma rays from Cygnus X-1: Modeling and nonthermal pair production

International Nuclear Information System (INIS)

Dermer, C.D.; Liang, E.P.

1988-02-01

The gamma-ray bump observed between 0.5 and 2 MeV in the spectrum of Cygnus X-1 can be interpreted as the thermal emissions from a hot (kT/approximately/400 keV) pair-dominated cloud. We argue that the X-rays and gamma rays are produced in separate emission regions, and calculate the photon-photon pair production rate from X-ray and gamma-ray interactions in the vicinity of Cyg X-1 by employing a simplified geometry for the two emitting regions

Total and regional bone mineral content in healthy Spanish subjects by dual-energy X-ray absorptiometry

International Nuclear Information System (INIS)

Aguado Henche, S.; Rodriguez Torres, R.; Clemente de Arriba, C.; Gomez Pellico, L.

2008-01-01

This is an observational cross-sectional study. The aim of the present study was to describe and analyze patterns of change in total and regional bone mineral content in relation to age and gender in a sedentary Spanish sample population (from the Community of Madrid). The age range of the sample population was from birth to 80 years. One thousand one hundred twenty healthy subjects were recruited and divided into 16 groups according to age. Each subject underwent whole-body densitometry using dual-energy X-ray absorptiometry. An analysis was made of the amount of bone mineral content (BMC) in the whole body and in different regions: the head, trunk, upper limbs, and lower limbs. Gender differences in mean values for upper limbs and lower limbs are statistically significant between 16 and 70 years of age. For the head and trunk, the mean BMC values show the most significant gender differences between 16 and 25 years of age (p≤0.001). Total bone mineral content (TBMC) and TBMC-to-height ratio show significant gender differences between 16 and 70 years of age. In females, TBMC values increase up to 20 years of age and in males up to 25 years of age. We have determined an evolutionary normal pattern of bone mineral content in urban Spanish people. (orig.)

Total and regional bone mineral content in healthy Spanish subjects by dual-energy X-ray absorptiometry

Energy Technology Data Exchange (ETDEWEB)

Aguado Henche, S.; Rodriguez Torres, R.; Clemente de Arriba, C.; Gomez Pellico, L. [Universidad de Alcala, Departamento de Anatomia y Embriologia Humana, Facultad de Medicina, Alcala de Henares, Madrid (Spain)

2008-11-15

This is an observational cross-sectional study. The aim of the present study was to describe and analyze patterns of change in total and regional bone mineral content in relation to age and gender in a sedentary Spanish sample population (from the Community of Madrid). The age range of the sample population was from birth to 80 years. One thousand one hundred twenty healthy subjects were recruited and divided into 16 groups according to age. Each subject underwent whole-body densitometry using dual-energy X-ray absorptiometry. An analysis was made of the amount of bone mineral content (BMC) in the whole body and in different regions: the head, trunk, upper limbs, and lower limbs. Gender differences in mean values for upper limbs and lower limbs are statistically significant between 16 and 70 years of age. For the head and trunk, the mean BMC values show the most significant gender differences between 16 and 25 years of age (p{<=}0.001). Total bone mineral content (TBMC) and TBMC-to-height ratio show significant gender differences between 16 and 70 years of age. In females, TBMC values increase up to 20 years of age and in males up to 25 years of age. We have determined an evolutionary normal pattern of bone mineral content in urban Spanish people. (orig.)

Late-replicating X-chromosome: replication patterns in mammalian females

Directory of Open Access Journals (Sweden)

Tunin Karen

2002-01-01

Full Text Available The GTG-banding and 5-BrdU incorporation patterns of the late-replicating X-chromosome were studied in female dogs and cattle, and compared to human female patterns. The replication patterns of the short arm of the X-chromosomes did not show any difference between human, dog and cattle females. As to the long arm, some bands showed differences among the three studied species regarding the replication kinetics pattern. These differences were observed in a restricted region of the X-chromosome, delimited by Xq11 -> q25 in humans, by Xq1 -> q8 in dogs, and by Xq12 -> q32 in cattle. In an attempt to find out if these differences in the replication kinetics could be a reflection of differences in the localization of genes in that region of the X-chromosome, we used the probe for the human androgen receptor gene (AR localized at Xq12, which is in the region where we observed differences among the three studied species. We did not, however, observe hybridization signals. Our study goes on, using other human probes for genes located in the region Xq11 -> Xq25.

The origin of two X-class flares in active region NOAA 12673. Shear flows and head-on collision of new and preexisting flux

Science.gov (United States)

Verma, Meetu

2018-05-01

Flare-prolific active region NOAA 12673 produced consecutive X2.2 and X9.3 flares on the 6 September 2017. To scrutinize the morphological, magnetic, and horizontal flow properties associated with these flares, a seven-hour time series was used consisting of continuum images, line-of-sight and vector magnetograms, and 1600 Å UV images. These data were acquired with the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA). The white-light flare emission differed for both flares, while the X2.2 flare displayed localized, confined flare kernels, the X9.3 flare exhibited a two-ribbon structure. In contrast, the excess UV emission exhibited a similar structure for both flares, but with larger areal extent for the X9.3 flare. These two flares represented a scenario in which the first confined flare acted as precursor, setting up the stage for the more extended flare. Difference maps for continuum and magnetograms revealed locations of significant changes, that is, penumbral decay and umbral strengthening. The curved magnetic polarity inversion line in the δ-spot was the fulcrum of most changes. Horizontal proper motions were computed using the differential affine velocity estimator for vector magnetograms (DAVE4VM). Persistent flow features included (1) strong shear flows along the polarity inversion line, where the negative, parasitic polarity tried to bypass the majority, positive-polarity part of the δ-spot in the north, (2) a group of positive-polarity spots, which moved around the δ-spot in the south, moving away from the δ-spot with significant horizontal flow speeds, and (3) intense moat flows partially surrounding the penumbra of several sunspots, which became weaker in regions with penumbral decay. The enhanced flare activity has its origin in the head-on collision of newly emerging flux with an already existing regular, α-spot. Umbral cores of emerging bipoles were incorporated in its penumbra, creating a δ-configuration with

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

Science.gov (United States)

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

2015-11-17

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

X-ray vision of fuel sprays

International Nuclear Information System (INIS)

Wang, J.

2005-01-01

With brilliant synchrotron X-ray sources, microsecond time-resolved synchrotron X-ray radiography and tomography have been used to elucidate the detailed three-dimensional structure and dynamics of high-pressure high-speed fuel sprays in the near-nozzle region. The measurement allows quantitative determination of the fuel distribution in the optically impenetrable region owing to the multiple scattering of visible light by small atomized fuel droplets surrounding the jet. X-radiographs of the jet-induced shock waves prove that the fuel jets become supersonic under appropriate injection conditions and that the quantitative analysis of the thermodynamic properties of the shock waves can also be derived from the most direct measurement. In other situations where extremely axial-asymmetric sprays are encountered, mass deconvolution and cross-sectional fuel distribution models can be computed based on the monochromatic and time-resolved X-radiographic images collected from various rotational orientations of the sprays. Such quantitative analysis reveals the never-before-reported characteristics and most detailed near-nozzle mass distribution of highly transient fuel sprays

X chromosome and suicide.

Science.gov (United States)

Fiori, L M; Zouk, H; Himmelman, C; Turecki, G

2011-02-01

Suicide completion rates are significantly higher in males than females in most societies. Although gender differences in suicide rates have been partially explained by environmental and behavioral factors, it is possible that genetic factors, through differential expression between genders, may also help explain gender moderation of suicide risk. This study investigated X-linked genes in suicide completers using a two-step strategy. We first took advantage of the genetic structure of the French-Canadian population and genotyped 722 unrelated French-Canadian male subjects, of whom 333 were suicide completers and 389 were non-suicide controls, using a panel of 37 microsatellite markers spanning the entire X chromosome. Nine haplotype windows and several individual markers were associated with suicide. Significant results aggregated primarily in two regions, one in the long arm and another in the short arm of chromosome X, limited by markers DXS8051 and DXS8102, and DXS1001 and DXS8106, respectively. The second stage of the study investigated differential brain expression of genes mapping to associated regions in Brodmann areas 8/9, 11, 44 and 46, in an independent sample of suicide completers and controls. Six genes within these regions, Rho GTPase-activating protein 6, adaptor-related protein complex 1 sigma 2 subunit, glycoprotein M6B, ribosomal protein S6 kinase 90  kDa polypeptide 3, spermidine/spermine N(1)-acetyltransferase 1 and THO complex 2, were found to be differentially expressed in suicide completers.

Synthesis, crystal structure investigation and magnetism of the complex metal-rich boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) with Th{sub 7}Fe{sub 3}-type structure

Energy Technology Data Exchange (ETDEWEB)

Misse, Patrick R.N.; Mbarki, Mohammed [Institute of Inorganic Chemistry, RWTH Aachen University, 52066 Aachen (Germany); Fokwa, Boniface P.T., E-mail: boniface.fokwa@ac.rwth-aachen.de [Institute of Inorganic Chemistry, RWTH Aachen University, 52066 Aachen (Germany)

2012-08-15

Powder samples and single crystals of the new complex boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) have been synthesized by arc-melting the elements under purified argon atmosphere on a water-cooled copper crucible. The products, which have metallic luster, were structurally characterized by single-crystal and powder X-ray diffraction as well as EDX measurements. Within the whole solid solution range the hexagonal Th{sub 7}Fe{sub 3} structure type (space group P6{sub 3}mc, no. 186, Z=2) was identified. Single-crystal structure refinement results indicate the presence of chromium at two sites (6c and 2b) of the available three metal Wyckoff sites, with a pronounced preference for the 6c site. An unexpected Rh/Ru site preference was found in the Ru-rich region only, leading to two different magnetic behaviors in the solid solution: The Rh-rich region shows a temperature-independent (Pauli) paramagnetism whereas an additional temperature-dependent paramagnetic component is found in the Ru-rich region. - Graphical abstract: The new complex boride series Cr{sub x}(Rh{sub 1-y}Ru{sub y}){sub 7-x}B{sub 3} (x=0.88-1; y=0-1) has been synthesized by arc melting the elements under purified argon atmosphere. Beside the 3d/4d site preference within the whole solid solution, an unexpected Rh/Ru site preference was found in the Ru-rich region only, leading to two different magnetic behaviors: The Rh-rich region shows a temperature-independent (Pauli) paramagnetism whereas an additional temperature-dependent paramagnetic component is found in the Ru-rich region. Highlights: Black-Right-Pointing-Pointer Synthesis of a new boride series fulfilling Vegard Acute-Accent s rule. Black-Right-Pointing-Pointer 3d/4d site preference. Black-Right-Pointing-Pointer Unexpected Ru/Rh site preference. Black-Right-Pointing-Pointer Rh-rich region is Pauli paramagnetic. Black-Right-Pointing-Pointer Ru-rich region is Pauli and temperature-dependent paramagnetic.

Sirenomelia with a de novo balanced translocation 46,X,t(X;16)(p11.23;p12.3).

Science.gov (United States)

Kurosawa, Kenji; Tanoshima-Takei, Miki; Yamamoto, Toshiyuki; Ishikawa, Hiroshi; Masuno, Mitsuo; Tanaka, Yukichi; Yamanaka, Michiko

2012-06-01

We report a female fetus with sirenomelia with 46,X,t(X;16)(p11.23;p12.3) de novo. Fluorescence in situ hybridization (FISH) with bacterial artificial chromosomes were employed for narrowing down the breakpoint regions. On chromosome 16, the breakpoint was mapped in the region of RP11-453F10 (19 920 640-20 118 153 bp from 16pter). On chromosome X, the breakpoint was mapped in the region of RP11-794A15 (47 333 744-47 524 066 bp from Xpter). This is the first case report of sirenomelia associated with translocations. The abnormal phenotype, associated with a balanced translocation, was caused by deletion or breakage of dosage-sensitive genes of the breakpoint, disruption of an imprinted gene, or uniparental disomy. Although the parental origin of normal 16 and der(16) remained undetermined, this case will provide insight into the pathogenetic mechanism of sirenomelia. © 2011 The Authors. Congenital Anomalies © 2011 Japanese Teratology Society.

Impedance/modulus analysis of sol-gel Ba{sub x}Sr{sub 1-x}TiO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Saif, Alaeddin A.; Poopalan, P. [University Malaysia Perlis, Perlis (Malaysia)

2010-12-15

Perovskite-structure-type sol-gel barium-strontium-titanate (BST) thin films with molar formula Ba{sub x}Sr{sub 1-x}TiO{sub 3} (x = 0.5, 0.6, 0.7, and 0.8) have been successfully fabricated as Al/BST/Pt capacitors. In order to study the role of the grain size in the conduction mechanisms, we present atomic force microscopy (AFM) results. The impedance and the electric modulus of Ba{sub x}Sr{sub 1-x}TiO{sub 3} thin films have been analyzed in order to correlate the effect of the film regional processes on the conduction mechanism. The impedance and the electric modulus complex planes show three overlapping regions as response for the bulk, the grain boundary and the film/electrode interface mechanisms, and an equivalent circuit has been proposed for each mechanism. The conduction mechanism resulting from the bulk and the grain boundaries is discussed; the results show that the grain boundaries have less effect on the conduction mechanism than the bulk.

Radiography in the X-ray region of a laser implosed microball

International Nuclear Information System (INIS)

Launspach, J.; Bayer, C.; Billon, D.; Decroisette, M.; Juraszek, D.; Meynial, D.

1981-05-01

The OCTAL laser of the Limeil CEA Research Center was used to realize the implosion of small targets containing a mixture of DT and to produce thermonuclear fusion reactions. The experimental device in which the experiments were carried out is called Camelia. Its main component is a vacuum chamber upon which the following elements are fixed: - devices for adjusting the focussing lenses; - a device for positioning targets; - extensive diagnostic means enabling the maximum amount of information to be obtained from each shot. These experiments were performed in order to study laser implosion mechanisms and to measure the density and temperature characteristics that can be reached in this way. The X-ray radiography device is relatively simple. It consists of an X-ray source, the target to be analyzed, one or two stenopies and a detector which is either a simple film (Kodak Kodirex) for diagnostics without temporal resolution or a scanning camera with a slit when temporal resolution is required. The device can be used: - without an x-ray source for emission diagnostics with spatio-temporal resolution, - to study the pre-heating of targets by radiography of the dust at the beginning of the implosion, - for diagnostics of the plasma core by radiography of dust after the implosion [fr

Investigation on transition behavior and electrical properties of (K0.5Na0.51-xLixNb0.84Ta0.1Sb0.06O3 around polymorphic phase transition region

Directory of Open Access Journals (Sweden)

Chen Zhu

2014-01-01

Full Text Available (K0.5Na0.51-xLixNb0.84Ta0.1Sb0.06O3 (KNLNTS lead free ceramics with different Li concentration were fabricated by conventional solid-state reaction method. By increasing Li ions in KNLNTS, the grains grow up and the crystal structure changes from orthorhombic to tetragonal. When 0.03 ≤ x ≤ 0.05, the ceramics structure lays in PPT region. Polarization versus electric field (P-E hysteresis loops at room temperature show good ferroelectric properties and the remnant polarization decreases by increasing Li content while coercive electric keeps almost unchanged. In PPT region, taking x = 0.04 as an example, the sample shows excellent dielectric properties: the dielectric constant is 1159 and loss tangent is 0.04, while the piezoelectric constant d33 is 245 pC/N and kp is 0.44 at room temperature, it is promising for (K0.5Na0.51-xLixNb0.84Ta0.1Sb0.06O3 with 4 at. % Li to substitute PZT.

Effect of grain boundary on electrical characteristics in B- and P-doped polycrystalline Si1-x-yGe xC y film deposited by ultraclean LPCVD

International Nuclear Information System (INIS)

Shim, Hyunyoung; Sakuraba, Masao; Murota, Junichi

2006-01-01

The effect of grain boundary on electrical characteristics in B- and P-doped polycrystalline (poly) Si 1-x -y Ge x C y films was investigated. Poly-Si 1-x -y Ge x C y films were deposited on thermally oxidized Si(100) at 500-650 deg. C in a SiH 4 -GeH 4 -SiH 3 CH 3 -H 2 gas mixture by an ultraclean hot-wall low-pressure chemical vapor deposition. B and P were doped into the films by ion implantation and diffusion by heat-treatment. The electrical properties are characterized by grain size, width of disordered region near grain boundaries, carrier trap density and the amount of impurity segregation at grain boundaries. In the B-doped poly-Si 1-x -y Ge x C y films heat-treated at 900 deg. C, the increase of carrier concentration n poly and the decrease of resistivity ρ poly with Ge addition are caused by the narrowing of the width of disordered regions, i.e., crystallization of disordered regions induced by Ge atoms. The decrease of n poly and the increase of ρ poly with C addition are explained by the suppression of crystallization of disordered region due to C atom segregation at grain boundaries. In the P-doped poly-Si 1-x -y Ge x C y films, it is found that n poly and ρ poly are influenced by P atom segregation at grain boundaries due to lowering solid solubility of P in grain by the existence of Ge

TiO2 Nanoparticles as a Soft X-ray Molecular Probe

Energy Technology Data Exchange (ETDEWEB)

Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B.; Hofmann, Cristina; Kanaras, Antonios G.; Kilcoyne, David A.; Le Gros, Mark; Yin, Yadong; Alivisatos, A. Paul; Larabell, Carolyn A.

2007-06-30

With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubules polymerized from biotinylated tubulin. The microtubules were imaged using scanning transmission x-ray microscopy (STXM), and the TiO2 nanoparticle tags were specifically identified using x-ray absorption near edge spectroscopy (XANES). These experiments demonstrate that TiO2 nanoparticles are potential probes for protein localization analyses using soft x-ray microscopy.

Simultaneous SMM flat crystal spectrometer and Very Large Array observations of solar active regions

Science.gov (United States)

Lang, Kenneth R.; Willson, Robert F.; Smith, Kermit L.; Strong, Keith T.

1987-01-01

High-resolution images of the quiescent emission from two solar active regions at 20 cm (VLA) and soft X-ray (SMM FCS) wavelengths are compared. There are regions where the X-ray coronal loops have been completely imaged at 20 cm wavelength. In other regions, the X-ray radiation was detected without detectable 20 cm radiation, and vice versa. The X-ray data were used to infer average electron temperatures of about 3-million K and average electron densities of about 2.5 x 10 to the 9th/cu cm for the X-ray emitting plasma in the two active regions. The thermal bremsstrahlung of the X-ray emitting plasma is optically thin at 20 cm wavelength. The 20 cm brightness temperatures were always less than T(e), which is consistent with optically thin bremsstrahlung. The low T(B) can be explained if a higher, cooler plasma covers the hotter X-ray emitting plasma. Thermal gyroresonance radiation must account for the intense 20 cm radiation near and above sunspots where no X-ray radiation is detected.

Scale dependence and small-x behaviour of polarized parton distributions

International Nuclear Information System (INIS)

Ball, R.D.; Forte, S.; Ridolfi, G.

1995-01-01

We discuss perturbative evolution of the polarized structure function g 1 in the (x, Q 2 ) plane, with special regard to the small-x region. We determine g 1 in terms of polarized quark and gluon distributions using coefficient functions to order α s . At small x g 1 then displays substantial scale dependence, which necessarily implies a corresponding scale dependence in the large-x region. This scale dependence has significant consequences for the extraction of the first moment from the experimental data, reducing its value while increasing the error. Conversely, the scale dependence may be used to constrain the size of the polarized gluon distribution. ((orig.))

Scale dependence and small x behaviour of polarized parton distributions

CERN Document Server

Ball, R D; Ridolfi, G; Forte, S; Ridolfi, G

1995-01-01

We discuss perturbative evolution of the polarized structure function g_1 in the (x,Q^2) plane, with special regard to the small-x region. We determine g_1 in terms of polarized quark and gluon distributions using coefficient functions to order alpha_s. At small x g_1 then displays substantial scale dependence, which necessarily implies a corresponding scale dependence in the large-x region. This scale dependence has significant consequences for the extraction of the first moment from the experimental data, reducing its value while increasing the error. Conversely, the scale dependence may be used to constrain the size of the polarized gluon distribution.

Test of the critical point symmetry X(5) in the mass region A=180

Energy Technology Data Exchange (ETDEWEB)

Melon, B.; Dewald, A.; Moeller, O.; Pissulla, T.; Fransen, C.; Jolie, J.; Linnemann, A.; Zell, K.O. [IKP, Univ. zu Koeln (Germany); Petkov, P. [Bulg. Acad. of Sciences, Inst. for Nucl. Res. and Nucl. Ener., Sofia (Bulgaria); Tonev, D.; Angelis, G. De; Bazzacco, D. [INFN, LN di Legnaro (Italy); Ur, C.; Menegazzo, R.; Farnea, E. [Dip. di Fisica, Univ.' and INFN Sez. Padova (Italy)

2007-07-01

Recently, the first examples of X(5) like nuclei in the mass region A=180 have been identified, {sup 176,178}Os. We report on further results of a lifetime measurement performed at the LN Legnaro using the Koeln coincidence plunger device and the GASP spectrometer. Excited states were populated via the reaction {sup 152}Sm({sup 29}Si,5n){sup 176}Os at E({sup 29}Si) = 145 MeV. Special effort has been made to reduce the experimental uncertainty of the B(E2, 2{sub 1}{sup +} {yields} 0{sub 1}{sup +}) value in {sup 178}Os, used for transition strength normalizations in {sup 178}Os necessary for the comparison with theoretical models. A second experiment was performed to measure the lifetime of the first excited 2{sup +} state in {sup 178}Os with the Koeln coincidence plunger device at the FN Tandem accelerator of the University of Cologne using THE {sup 166}Er({sup 16}O,4n){sup 178}Os reaction at E({sup 16}O) = 80 MeV. The resulting lifetime has been compared to the value obtained using the delayed coincidence method. (orig.)

SMM x ray polychromator

Science.gov (United States)

Saba, J. L. R.

1993-01-01

The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

Regional assignment of seven loci to 12p 13. 2-pter by PCR analysis of somatic cell hybrids containing the der(12) or the der(X) chromosome from a mesothelioma showing t(X; 12)(q22; p13)

Energy Technology Data Exchange (ETDEWEB)

Aerssens, J.; Chaffanet, M.; Baens, M.; Matthijs, G.; Van Den Berche, H.; Cassiman, J.J.; Marynen, P. (Arthritis and Metabolic Bone Disease Research Unit, Leuven (Belgium))

1994-03-01

Two somatic cell hybrids containing the der(12) or the der(X) from a mesothelioma with a translocation t(X;12) (q22;p13) as the only chromosomal change were generated to characterize the region of 12p12 containing the translocation breakpoint. Fluorescence in situ hybridization analysis showed the breakpoint on chromosome 12 to occur between VWF and D12S158. On the linkage map developed by J. Weissenbach et al., the breakpoints were located between DXS1106 and DCS1001 on chromosome X. PCR analysis based on genomic sequences, with DNA from both somatic cell hybrids, enabled mapping of CACNL1A1, FGF6, D12S370, D12S38OE, D12S381E, and D12S382E distally to the 12p13 breakpoint and to VWF. 11 refs., 2 figs., 1 tab.

Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

Science.gov (United States)

Marlowe, H.; Kaaret, P.; Lang, C.; Feng, H.; Grisé, F.; Miller, N.; Cseh, D.; Corbel, S.; Mushotzky, R. F.

2014-10-01

We observed the Ultraluminous X-ray Source (ULX) IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No significant radio emission above the rms noise level was observed within the region of the ULX, consistent with the interpretation as a thermal state though other states cannot be entirely ruled out with the current data. We estimate the mass of the black hole using the modelled inner disc temperature to be 30 M_{⊙} ≲ M√{cosi}≲ 200 M_{⊙} based on a Shakura-Sunyaev disc model. Through a study of the hardness and high-energy curvature of available X-ray observations, we find that the accretion state of X-1 is not determined by luminosity alone.

Active silicon x-ray for measuring electron temperature

International Nuclear Information System (INIS)

Snider, R.T.

1994-07-01

Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

Helicity dependence of the γ {sup 3}He → πX reactions in the Δ(1232) resonance region

Energy Technology Data Exchange (ETDEWEB)

Costanza, S.; Rigamonti, F. [INFN, Sezione di Pavia, Pavia (Italy); Universita di Pavia, Dipartimento di Fisica, Pavia (Italy); Mushkarenkov, A.; Braghieri, A.; Pedroni, P. [INFN, Sezione di Pavia, Pavia (Italy); Romaniuk, M.; Mandaglio, G. [INFN, Sezione di Catania, Catania (Italy); Universita di Messina, Dipartimento di Fisica e Scienze della Terra, Messina (Italy); Aguar Bartolome, P.; Ahrens, J.; Arends, H.J.; Heid, E.; Jahn, O.; Kashevarov, V.L.; Ostrick, M.; Ortega, H.; Otte, P.B.; Oussena, B.; Schumann, S.; Thomas, A.; Unverzagt, M. [Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; Rosner, G. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Beck, R. [University of Bonn, Helmholtz-Institut fuer Strahlen und Kernphysik, Bonn (Germany); Bekrenev, V.; Kruglov, S.; Kulbardis, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Berghaeuser, H.; Drexler, P.; Metag, V.; Thiel, M. [University of Giessen, II Physikalisches Institut, Giessen (Germany); Briscoe, W.J.; Downie, E.J. [The George Washington University, Washington, DC (United States); Cherepnya, S.N.; Fil' kov, L.V.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Collicott, C. [Dalhousie University, Halifax, NS (Canada); Saint Mary' s University, Halifax, NS (Canada); Fix, A. [Tomsk Polytechnic University, Tomsk (Russian Federation); Glazier, D.I. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); University of Edinburgh, SUPA School of Physics and Astronomy, Edinburgh (United Kingdom); Heil, W.; Krimmer, J. [Universitaet Mainz, Institut fuer Physik, Mainz (Germany); Hornidge, D.; Middleton, D.G. [Mount Allison University, Sackville, NB (Canada); Jaegle, I.; Keshelashvili, I.; Krusche, B.; Oberle, M.; Pheron, F.; Rostomyan, T.; Werthmueller, D. [University of Basel, Institut fuer Physik, Basel (Switzerland); Huber, G.M. [University of Regina, Regina, SK (Canada); Jude, T.; Watts, D.P. [University of Edinburgh, SUPA School of Physics and Astronomy, Edinburgh (United Kingdom); Kondratiev, R. [Lebedev Physical Institute, Moscow (Russian Federation); Korolija, M.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Manley, D.M. [Kent State University, Kent, Ohio (United States); Nefkens, B.M.K.; Starostin, A. [University of California, Los Angeles, California (United States); Nikolaev, A. [Universita di Pavia, Dipartimento di Fisica, Pavia (Italy); Prakhov, S. [Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Washington, DC (United States); University of California, Los Angeles, California (United States); Sarty, A.J. [Saint Mary' s University, Halifax, NS (Canada); Collaboration: A2 Collaboration

2014-11-15

The helicity dependences of the differential cross sections for the semi-inclusive γ {sup 3}He → π{sup 0} X and γ {sup 3}He → π{sup ±} X reactions have been measured for the first time in the energy region 200 < E{sub γ} 450 MeV. The experiment was performed at the tagged photon beam facility of the MAMI accelerator in Mainz using a longitudinally polarised high-pressure {sup 3}He gas target. Hadronic products were measured with the large-acceptance Crystal Ball detector complemented with additional devices for charged-particle tracking and identification. Unpolarised differential cross sections and their helicity dependence are compared with theoretical calculations using the Fix-Arenhoevel model. The effect of the intermediate excitation of the Δ(1232) resonance can be clearly seen from this comparison, especially for the polarised case, where nuclear effects are relatively small. The model provides a better theoretical description of the unpolarised charged pion photoproduction data than the neutral pion channel. It does significantly better in describing the helicity-dependent data in both channels. These comparisons provide new information on the mechanisms involved in pion photoproduction on {sup 3}He and suggest that a polarised {sup 3}He target can provide valuable information on the corresponding polarised quasi-free neutron reactions. (orig.)

Staphylococcal enterotoxin-like X (SElX is a unique superantigen with functional features of two major families of staphylococcal virulence factors.

Directory of Open Access Journals (Sweden)

Ries J Langley

2017-09-01

Full Text Available Staphylococcus aureus is an opportunistic pathogen that produces many virulence factors. Two major families of which are the staphylococcal superantigens (SAgs and the Staphylococcal Superantigen-Like (SSL exoproteins. The former are immunomodulatory toxins that induce a Vβ-specific activation of T cells, while the latter are immune evasion molecules that interfere with a wide range of innate immune defences. The superantigenic properties of Staphylococcal enterotoxin-like X (SElX have recently been established. We now reveal that SElX also possesses functional characteristics of the SSLs. A region of SElX displays high homology to the sialyl-lactosamine (sLacNac-specific binding site present in a sub-family of SSLs. By analysing the interaction of SElX with sLacNac-containing glycans we show that SElX has an equivalent specificity and host cell binding range to the SSLs. Mutation of key amino acids in this conserved region affects the ability of SElX to bind to cells of myeloid origin and significantly reduces its ability to protect S. aureus from destruction in a whole blood killing (WBK assay. Like the SSLs, SElX is up-regulated early during infection and is under the control of the S. aureus exotoxin expression (Sae two component gene regulatory system. Additionally, the structure of SElX in complex with the sLacNac-containing tetrasaccharide sialyl Lewis X (sLeX reveals that SElX is a unique single-domain SAg. In summary, SElX is an 'SSL-like' SAg.

Present status and future prospect of x-ray microscopes. Is it possible to realize x-ray 1 nm imaging?

International Nuclear Information System (INIS)

Aoki, Sadao

2010-01-01

High resolution X-ray imaging has been developed by using various optical elements and optical systems. In the soft X-ray region (∼3 nm) about 20 nm spatial resolution has been obtained, while in the hard X-ray (∼0.1 nm) about 50 nm. In the research frontier the spatial resolution better than 10 nm has been reported. The possibility to approach 1 nm spatial resolution is presented. (author)

Magnetic and thermophysical properties of Gd(X)Mn(1-X)S solid solutions.

Science.gov (United States)

Aplesnin, S S; Romanova, O B; Gorev, M V; Velikanov, D A; Gamzatov, A G; Aliev, A M

2013-01-16

The structural, magnetic, and thermophysical properties of cation-substituted sulfides Gd(X)Mn(1-X)S (0.04 ≤ X ≤ 0.25) with the NaCl-type face-centered cubic lattice have been investigated. The range of existence of long-range antiferromagnetic order has been established. The anomalies observed in the temperature dependence of the specific heat correspond to the temperatures of the magnetic phase transition. The anomaly in the specific heat caused by electron transitions between the 4f levels and d band states has been observed. It has been found that the coefficient of thermal expansion decreases with increasing concentration of substituents in the magnetically ordered region and remains nearly invariable in the paramagnetic phase.

Higher twist contributions to the structure functions F{sub 2}(x, Q{sup 2}) and g{sub 2}(x, Q{sup 2})

Energy Technology Data Exchange (ETDEWEB)

Bluemlein, Johannes; Boettcher, Helmut

2012-07-15

We report on recent results on higher twist contributions to the unpolarized structure functions F{sup p,d}{sub 2}(x,Q{sup 2}) at N{sup 3}LO in the large x region and constraints on the twist-3 contribution to polarized structure function g{sub 2}(x,Q{sup 2}).

Staging structures of the intercalation compounds Ag/sub x/TiS2

International Nuclear Information System (INIS)

Bardhan, K.K.; Kirczenow, G.; Jackle, G.; Irwin, J.C.

1986-01-01

An extensive investigation of the structure, and in particular the staging, of powdered samples of the intercalation compounds Ag/sub x/TiS 2 (0 0 C. The (T,x) phase diagram contains three phases: a high-x (dense) stage-1 phase, a stage-disordered phase, which at low x or high temperatures appears to become a pure low-x (dilute) stage-1 phase, and a simple stage-2 phase. On the high-x side of its stability region the stage-2 phase undergoes an apparent first-order transition to the dense stage-1 phase, but on the high-temperature side it proceeds continuously, through stage-disordered states, to a dilute stage-1 phase. On the low-x side of the stage-2 region there is also a dilute stage-1 phase. At sufficiently high temperatures a novel coexistence of the two stage-1 phases is observed. This is the first time that the high-temperature stability limit of the stage-2 region has been probed in any intercalation compound. The results are compared with recent theoretical models

Development of X-ray excitable luminescent probes for scanning X-ray microscopy

International Nuclear Information System (INIS)

Moronne, M.M.

1999-01-01

Transmission soft X-ray microscopy is now capable of achieving resolutions that are typically 5 times better than the best-visible light microscopes. With expected improvements in zone plate optics, an additional factor of two may be realized within the next few years. Despite the high resolution now available with X-ray microscopes and the high X-ray contrast provided by biological molecules in the soft X-ray region (λ=2-5 nm), molecular probes for localizing specific biological targets have been lacking. To circumvent this problem, X-ray excitable molecular probes are needed that can target unique biological features. In this paper we report our initial results on the development of lanthanide-based fluorescent probes for biological labeling. Using scanning luminescence X-ray microscopy (SLXM, Jacobsen et al., J. Microscopy 172 (1993) 121-129), we show that lanthanide organo-polychelate complexes are sufficiently bright and radiation resistant to be the basis of a new class of X-ray excitable molecular probes capable of providing at least a fivefold improvement in resolution over visible light microscopy. Lanthanide probes, able to bind 80-100 metal ions per molecule, were found to give strong luminescent signals with X-ray doses exceeding 10 8 Gy, and were used to label actin stress fibers and in vitro preparations of polymerized tubulin. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Q2 dependence of the spin structure function in the resonance region

International Nuclear Information System (INIS)

Li, Z.; Li, Z.

1994-01-01

In this paper, we show what we can learn from the CEBAF experiments on spin-structure functions, and the transition from the Drell-Hearn-Gerasimov sum rule in the real photon limit to the spin-dependent sum rules in deep inelastic scattering, and how the asymmetry A 1 (x,Q 2 ) approaches the scaling limit in the resonance region. The spin structure function in the resonance region alone cannot determine the spin-dependent sum rule due to the kinematic restriction of the resonance region. The integral ∫ 0 1 {A 1 (x,Q 2 )F 2 (x,Q 2 )/2x[1+R(x,Q 2 )]}dx is estimated from Q 2 =0--2.5 GeV 2 . The result shows that there is a region where both contributions from the baryon resonances and the deep inelastic scattering are important; thus it provides important information on the high twist effects on the spin-dependent sum rule

Multi-layer x-ray screens

International Nuclear Information System (INIS)

Rabatin, J.G.

1984-01-01

Rare earth oxyhalide phosphors activated with thulium ion are employed in X-ray intensifying screens having modified ultraviolet emission characteristics which reduce crossover effects without significant reduction in film speed and further increases screen brightness. Relatively low concentration levels of the thulium activator ion have been found to shift the ultraviolet emission of said phosphor when excited by X-rays to lower wavelengths in both the ultraviolet and near-ultraviolet spectral regions

X-ray generation by femtosecond laser pulses and its application to soft X-ray imaging microscope

International Nuclear Information System (INIS)

Ikeda, Kenichi; Kotaki, Hideyuki; Nakajima, Kazuhisa

2002-01-01

We have developed laser-produced plasma X-ray sources using femtosecond laser pulses at 10Hz repetition rate in a table-top size in order to investigate basic mechanism of X-ray emission from laser-matter interactions and its application to a X-ray microscope. In a soft X-ray region over 5 nm wavelength, laser-plasma X-ray emission from a solid target achieved an intense flux of photons of the order of 1011 photons/rad per pulse with duration of a few 100 ps, which is intense enough to make a clear imaging in a short time exposure. As an application of laser-produced plasma X-ray source, we have developed a soft X-ray imaging microscope operating in the wavelength range around 14 nm. The microscope consists of a cylindrically ellipsoidal condenser mirror and a Schwarzshird objective mirror with highly-reflective multilayers. We report preliminary results of performance tests of the soft X-ray imaging microscope with a compact laser-produced plasma X-ray source

Study of CeO{sub x}, PrO{sub x}, and Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}} films on Si(111) by means of high-energetic X-ray photoelectron spectroscopy; Untersuchung von CeO{sub x}-, PrO{sub x}- und Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}}- Filmen auf Si (111) mittels hochenergetischer Roentgen-Photoelektronenspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Allahgholi, Aschkan

2013-03-15

The intention of this work is to shed light on two much discussed topics in the study of rare earth oxides (REO) by hard x-ray photoelectron spectroscopy (HAXPES): (i) Due to the complex spectral shape of the Ce3d region, there have been many discussions on proper approaches to determine the concentration of Ce{sup 3+} and Ce{sup 4+} species in CeO{sub x} over the last decades. (ii) Recently, the true electron structure of rare earth oxides gained new attention, since ab initio calculations showed the necessity of considering additional inter atomic charge transfer to Ce5d levels. Using HAXPES and resonant HAXPES, the question of the true electronic structure of rare earth oxides is approached from the experimental side. As a third topic, the obtained results for cerium oxide and praseodymium oxide are applied in order to investigate the plasma oxidized mixed oxide Ce{sub x}Pr{sub 1-x}O{sub 2-{delta}} grown on Si(111) during thermal reduction. (orig.)

X-ray signs of traumas of the cervical region of the spinal cord in the acute period

International Nuclear Information System (INIS)

Brodskaya, Z.L.

1983-01-01

The results are analyzed of an X-ray examination of 208 patients with traumas of the cervical region of the spinal column and spinal cord in the acute period of trauma. The authors proposed a scheme that included telespondylography in standard and oblique projections, flebospondylography, discography and pneumomyelography in the Schantz collar with a patient lying on the back. Four types of the spinal cord traumas were diagnosed: compression with osseous elements (76.92%), with sharp discs and strained epidural hematomas (3.85%), isolated contusion of the spinal cord (10.1%) and disorder of the spinal circulation (9.13%). Special emphasis was laid on clinicospondylographic correlations, a critical distance, congenital narrowing of the vertebral canal. The concept of traumatic decompression of the spinal cord was stressed. Symptoms of its contusion and trauma of the spinal circulation were indicated

Near edge x-ray spectroscopy theory

International Nuclear Information System (INIS)

1994-01-01

We propose to develop a quantitative theory of x-ray spectroscopies in the near edge region, within about 100 eV of threshold. These spectroscopies include XAFS (X-ray absorption fine structure), photoelectron diffraction (PD), and diffraction anomalous fine structure (DAFS), all of which are important tools for structural studies using synchrotron radiation x-ray sources. Of primary importance in these studies are many-body effects, such as the photoelectron self-energy, and inelastic losses. A better understanding of these quantities is needed to obtain theories without adjustable parameters. We propose both analytical and numerical calculations, the latter based on our x-ray spectroscopy codes FEFF

The X-ray footprint of the circumnuclear disc

Science.gov (United States)

Mossoux, Enmanuelle; Eckart, Andreas

2018-03-01

We studied the central regions of the Galactic Centre to determine if the circumnuclear disc (CND) acts as an absorber or a barrier for the central X-rays diffuse emission. After reprocessing 4.6 Ms of Chandra observations, we were able to detect, for the first time, a depression in the X-ray luminosity of the diffuse emission whose size and location correspond to those of the CND. We extracted the X-ray spectra for various regions inside the CND footprint as well as for the region where the footprint is observed and for a region located outside the footprint. We simultaneously fitted these spectra as an optically thin plasma whose absorption by the interstellar medium (ISM) and by the local plasma were fitted independently using the Markov chain Monte Carlo method. The hydrogen column density of the ISM is 7.5 × 1022 cm-2. The X-ray diffuse emission inside the CND footprint is formed by a 2T plasma of 1 and 4 keV with slightly super-solar abundances except for the iron and carbon that are sub-solar. The plasma from the CND, in turn, is better described by a 1T model with abundances and local hydrogen column density that are very different from those of the innermost regions. The large iron abundance in this region confirms that the CND is dominated by the shock-heated ejecta of the Sgr A East supernova remnant. We deduced that the CND rather acts as a barrier for the Galactic Centre plasma and that the plasma located outside the CND may correspond to the collimated outflow possibly created by Sgr A* or the interaction between the wind of massive stars and the mini-spiral material.

X-ray Absorption and Diffraction Studies of the Mixed-phase State of (CrxV1-x)2O3

Energy Technology Data Exchange (ETDEWEB)

D Pease; A Frenkel; V Krayzman; T Huang; P Shanthakumar; J Budnick; P Metcalf; F Chudnovsky; E Stern

2011-12-31

X-ray diffraction and vanadium x-ray absorption near-edge structure (XANES) data have been obtained for (V{sub 1-x}Cr{sub x}){sub 2}O{sub 3} samples containing several concentrations of Cr, crossing the metal-insulator transition boundary. For single-phase single-crystal samples our theoretical results are generally in good qualitative agreement with our experimental single-crystal XANES, for both crystal orientations relative to the incident-beam electric vector. However, an anomalous peak occurs for both orientations in the K pre-edge of the single-crystal sample containing 1.2% Cr, a paramagnetic insulator sample that is in the concentration regime corresponding to the room-temperature two-phase (coexistence) region of the phase diagram. Upon increasing the temperature of the 0.4% Cr powdered material to 400 K so that one enters the two-phase region of the phase diagram, a similar peak appears and then diminishes at 600 K. These results, as well as experiments done by others involving room-temperature and low-temperature XANES of a 1.1% Cr sample, suggest that this feature in the V pre-edge structure is associated with the appearance under some circumstances of a small amount of highly distorted VO{sub 6} octahedra in the interface region between coexisting metal and insulating phases. Finally, we find that, for the two-phase regime, the concentration ratio of the metal-to-insulating phase varies between different regions from a sample batch of uniform composition made by the skull melting method.

Deeply inelastic scattering at small x in 20 min

International Nuclear Information System (INIS)

Levin, E.M.

1992-01-01

A status report is presented on new phenomena that are anticipated in deeply inelastic scattering in the low x→0 region. A summary of the theoretical situation in the region of small x is given, including the importance for the understanding of high energy interaction in QCD, and the low x behaviour of deep inelastic structure function. This new area of physics will be studied experimentally at HERA. (R.P.) 16 refs.; 6 figs

Assessment of radargrammetric DSMs from TerraSAR-X Stripmap images in a mountainous relief area of the Amazon region

Science.gov (United States)

de Oliveira, Cleber Gonzales; Paradella, Waldir Renato; da Silva, Arnaldo de Queiroz

The Brazilian Amazon is a vast territory with an enormous need for mapping and monitoring of renewable and non-renewable resources. Due to the adverse environmental condition (rain, cloud, dense vegetation) and difficult access, topographic information is still poor, and when available needs to be updated or re-mapped. In this paper, the feasibility of using Digital Surface Models (DSMs) extracted from TerraSAR-X Stripmap stereo-pair images for detailed topographic mapping was investigated for a mountainous area in the Carajás Mineral Province, located on the easternmost border of the Brazilian Amazon. The quality of the radargrammetric DSMs was evaluated regarding field altimetric measurements. Precise topographic field information acquired from a Global Positioning System (GPS) was used as Ground Control Points (GCPs) for the modeling of the stereoscopic DSMs and as Independent Check Points (ICPs) for the calculation of elevation accuracies. The analysis was performed following two ways: (1) the use of Root Mean Square Error (RMSE) and (2) calculations of systematic error (bias) and precision. The test for significant systematic error was based on the Student's-t distribution and the test of precision was based on the Chi-squared distribution. The investigation has shown that the accuracy of the TerraSAR-X Stripmap DSMs met the requirements for 1:50,000 map (Class A) as requested by the Brazilian Standard for Cartographic Accuracy. Thus, the use of TerraSAR-X Stripmap images can be considered a promising alternative for detailed topographic mapping in similar environments of the Amazon region, where available topographic information is rare or presents low quality.

Tc-99m Methoxy Isobutyl Isonitrile (MIBI) scintimammography for detection of loco-regional recurrence of breast cancer: A comparative study of scintimammography, X-ray mammography and breast ultrasound imaging

International Nuclear Information System (INIS)

Usmani, S.; Niaz, K.; Ahmed, N.; Niyaz, K.; Khan, H.A.; Javed, A.; Mohannadi, S.A.; Huda, F.A.

2007-01-01

Breast cancer is the most common cancer among women and the second leading cause of death in women after lung cancer. Local recurrence rate is about 1-2% per year. It is important to find a sensitive and accurate diagnostic method for early detection of recurrent tumor for planning subsequent management. The principal aim of the present study was to assess the utility of Tc-99m MIBI scintimammography in the detection of loco-regional recurrence of breast cancer in comparison with the conventionally used methods like x-ray mammography and ultrasonography. A total number of 42 patients (Age: mean= 45.55 yrs; median = 43.5; range, 22-77 yrs) suspected to have loco-regional recurrence of breast cancer on the basis of clinical examination and/or conventional imaging procedures were included in this study. All patients were subjected to planar scintimammography (SMM), SPECT imaging of the breast, x-ray mammography and Ultrasound scanning. The results were correlated with the final diagnosis arrived at by fine needle aspiration cytology (FNAC), core biopsy or definite wide local excision. Sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and accuracy (ACC) of scintimammography in the diagnosis of recurrent disease were found to be 82.75, 92.3, 96.0, 70.58 and 85.71% respectively; compared to 45.83, 66.6, 78.57, 31.57, 51.51 for x-ray mammography and 65.51, 69.23, 82.6, 47.36, 66.66 for Ultrasonography. Scintimammography results were correlated with x-ray mammography and ultrasonography by applying Pearson correlation. No significant correlation was found between SMM and XMM (r=0.27) or SMM and US (r=0.23). Based on the results of this study it is concluded that SMM has better diagnostic accuracy than mammography and ultrasonography in the detection of loco-regional recurrence of breast cancer. (author)

Method of producing a pseudo-color photograph with X-rays

Energy Technology Data Exchange (ETDEWEB)

Tajima, M

1965-05-08

Conventional black and white X-ray photography cannot simultaneously produce an image on photographic film of a subject having regions of high and low X-ray absorption due to the limitation of photographic density range, gradation and exposure tolerance. This invention records both regions as images of different colors on the same color photographic film. According to a method of this invention for making an X-ray pseudo-color photograph, the subject is directly irradiated by an X-ray beam emergent from an X-ray beam generator, and an X-ray permeation image of the subject is converted into and displayed as a visible light image by means of a fluorescent screen. In one aspect of this invention, there is used a color photographic film which has at least two kinds of sensitive and coloring layers exhibiting the same sensitivity. During the period in which the visible image is displayed, the film is exposed to the visible light in such a way that at least two color filters differing in color and density are successively interposed between the film and the fluorescent screen. In another aspect, a color photographic film is employed having at least two kinds of sensitive and coloring layers exhibiting different sensitivities. During the period in which the visible image is displayed, the film is exposed to visible light by sequentially interposing at least two color filters of different color but of equal density. In this manner, regions comparatively low in X-ray absorption, such as the lungs, and regions comparatively high in absorption, such as the heart, appear as, for example, a blue image and a red image on the color photographic film, respectively.

Refined mapping and YAC contig construction of the X-linked cleft palate and ankyloglossia locus (CPX) including the proximal X-Y homology breakpoint within Xq21.3

Energy Technology Data Exchange (ETDEWEB)

Forbes, S.A.; Brennan, L.; Richardson, M. [Queen Charlotte`s Hospital, London (United Kingdom)] [and others

1996-01-01

The gene for X-linked cleft palate (CPX) has previously been mapped in an Icelandic kindred between the unordered proximal markers DXS1002/DXS349/DXS95 and the distal marker DXYS1X, which maps to the proximal end of the X-Y homology region in Xq21.3. Using six sequence-tagged sites (STSs) within the region, a total of 91 yeast artificial chromosome (YAC) clones were isolated and overlapped in a single contig that spans approximately 3.1 Mb between DXS1002 and DXYS1X. The order of microsatellite and STS markers in this was established as DXS1002-DXS1168-DXS349-DXS95-DXS364-DXS1196-DXS472-DXS1217-DXYS1X. A long-range restriction map of this region was created using eight nonchimeric, overlapping YAC clones. Analysis of newly positioned polymorphic markers in recombinant individuals from the Icelandic family has enabled us to identify DXS1196 and DXS1217 as the flanking markers for CPX. The maximum physical distance containing the CPX gene has been estimated to be 2.0 Mb, which is spanned by a minimum set of five nonchimeric YAC clones. In addition, YAC end clone and STS analyses have pinpointed the location of the proximal boundary of the X-Y homology region within the map. 40 refs., 2 figs., 2 tabs.

Inverted repeats in the promoter as an autoregulatory sequence for TcrX in Mycobacterium tuberculosis

International Nuclear Information System (INIS)

Bhattacharya, Monolekha; Das, Amit Kumar

2011-01-01

Highlights: ► The regulatory sequences recognized by TcrX have been identified. ► The regulatory region comprises of inverted repeats segregated by 30 bp region. ► The mode of binding of TcrX with regulatory sequence is unique. ► In silico TcrX–DNA docked model binds one of the inverted repeats. ► Both phosphorylated and unphosphorylated TcrX binds regulatory sequence in vitro. -- Abstract: TcrY, a histidine kinase, and TcrX, a response regulator, constitute a two-component system in Mycobacterium tuberculosis. tcrX, which is expressed during iron scarcity, is instrumental in the survival of iron-dependent M. tuberculosis. However, the regulator of tcrX/Y has not been fully characterized. Crosslinking studies of TcrX reveal that it can form oligomers in vitro. Electrophoretic mobility shift assays (EMSAs) show that TcrX recognizes two regions in the promoter that are comprised of inverted repeats separated by ∼30 bp. The dimeric in silico model of TcrX predicts binding to one of these inverted repeat regions. Site-directed mutagenesis and radioactive phosphorylation indicate that D54 of TcrX is phosphorylated by H256 of TcrY. However, phosphorylated and unphosphorylated TcrX bind the regulatory sequence with equal efficiency, which was shown with an EMSA using the D54A TcrX mutant.

Fabrication of Coaxial Si(1-x)Ge(x) Heterostructure Nanowires by O(2) Flow-Induced Bifurcate Reactions.

Science.gov (United States)

Kim, Ilsoo; Lee, Ki-Young; Kim, Ungkil; Park, Yong-Hee; Park, Tae-Eon; Choi, Heon-Jin

2010-06-17

We report on bifurcate reactions on the surface of well-aligned Si(1-x)Ge(x) nanowires that enable fabrication of two different coaxial heterostructure nanowires. The Si(1-x)Ge(x) nanowires were grown in a chemical vapor transport process using SiCl(4) gas and Ge powder as a source. After the growth of nanowires, SiCl(4) flow was terminated while O(2) gas flow was introduced under vacuum. On the surface of nanowires was deposited Ge by the vapor from the Ge powder or oxidized into SiO(2) by the O(2) gas. The transition from deposition to oxidation occurred abruptly at 2 torr of O(2) pressure without any intermediate region and enables selectively fabricated Ge/Si(1-x)Ge(x) or SiO(2)/Si(1-x)Ge(x) coaxial heterostructure nanowires. The rate of deposition and oxidation was dominated by interfacial reaction and diffusion of oxygen through the oxide layer, respectively.

Investigating the role of X chromosome breakpoints in premature ovarian failure

Directory of Open Access Journals (Sweden)

Baronchelli Simona

2012-07-01

Full Text Available Abstract The importance of the genetic factor in the aetiology of premature ovarian failure (POF is emphasized by the high percentage of familial cases and X chromosome abnormalities account for 10% of chromosomal aberrations. In this study, we report the detailed analysis of 4 chromosomal abnormalities involving the X chromosome and associated with POF that were detected during a screening of 269 affected women. Conventional and molecular cytogenetics were valuable tools for locating the breakpoint regions and thus the following karyotypes were defined: 46,X,der(Xt(X;19(p21.1;q13.42mat, 46,X,t(X;2(q21.33;q14.3dn, 46,X,der(Xt(X;Y(q26.2;q11.223mat and 46,X,t(X;13(q13.3;q31dn. A bioinformatic analysis of the breakpoint regions identified putative candidate genes for ovarian failure near the breakpoint regions on the X chromosome or on autosomes that were involved in the translocation event. HS6ST1, HS6ST2 and MATER genes were identified and their functions and a literature review revealed an interesting connection to the POF phenotype. Moreover, the 19q13.32 locus is associated with the age of onset of the natural menopause. These results support the position effect of the breakpoint on flanking genes, and cytogenetic techniques, in combination with bioinformatic analysis, may help to improve what is known about this puzzling disorder and its diagnostic potential.

Mass transfer in stellar X-ray sources

International Nuclear Information System (INIS)

Verbunt, F.

1982-01-01

This thesis deals with mass transfer in the binary stars that emit X-rays. Optical observations on two sources are presented: 2A0311-227 and Cen X-4. The transferred matter will often enter a gaseous disk around the compact star, and spiral inwards slowly through this disk. The conditions for the formation of such a disk are investigated and the equations governing its structure are presented. Different models are discussed and it is concluded that different models lead to very similar results for those regions of the disk where gas pressure is more important than radiative pressure, and that these results agree fairly well with observations. No consistent model has been constructed as yet for the region where radiative pressure is dominant. Theoretically one predicts that the optical light emitted by a disk around a neutron star is mainly caused by X-ray photons from the immediate surroundings of the neutron star that hit the outer disk surface, are absorbed, thermalised, and re-emitted in the optical and ultraviolet regions of the spectrum. This expectation is verified by comparison with the collected observational data of low-mass X-ray binaries. Finally the author investigates which mechanism is responsible for the mass transfer in systems where the mass-losing star is less massive than the sun. (Auth.)

The whispering gallery as an optical component in the X-ray region

International Nuclear Information System (INIS)

Howells, M.R.

1995-08-01

The whispering gallery phenomenon in acoustics has been known and studied for more than a century, and the same effect has been observed to take place with waves other than sound waves. In this paper we review the theoretical basis and attractive features of the whispering gallery as a soft x-ray optical component and indicate some of its potential applications. We then describe what may be its most unique capability which, in favorable cases, is to provide a way. to manipulate the phase difference between the s and p polarization components and thus to generate circularly or elliptically polarized soft x-rays

Quasi-static three-dimensional magnetic field evolution in solar active region NOAA 11166 associated with an X1.5 flare

International Nuclear Information System (INIS)

Vemareddy, P.; Wiegelmann, T.

2014-01-01

We study the quasi-static evolution of coronal magnetic fields constructed from the non-linear force-free field (NLFFF) approximation aiming to understand the relation between the magnetic field topology and ribbon emission during an X1.5 flare in active region (AR) NOAA 11166. The flare with a quasi-elliptical and two remote ribbons occurred on 2011 March 9 at 23:13 UT over a positive flux region surrounded by negative flux at the center of the bipolar AR. Our analysis of the coronal magnetic structure with potential and NLFFF solutions unveiled the existence of a single magnetic null point associated with a fan-spine topology and is co-spatial with the hard X-ray source. The footpoints of the fan separatrix surface agree with the inner edge of the quasi-elliptical ribbon and the outer spine is linked to one of the remote ribbons. During the evolution, the slow footpoint motions stressed the field lines along the polarity inversion line and caused electric current layers in the corona around the fan separatrix surface. These current layers trigger magnetic reconnection as a consequence of dissipating currents, which are visible as cusp-shaped structures at lower heights. The reconnection process reorganized the magnetic field topology whose signatures are observed at the separatrices/quasi-separatrix layer structure in both the photosphere and the corona during the pre-to-post flare evolution. In agreement with previous numerical studies, our results suggest that the line-tied footpoint motions perturb the fan-spine system and cause null point reconnection, which eventually causes the flare emission at the footpoints of the field lines.

The disordering phase transformation in (Ni/sub 70/Fe/sub 30/)/sub 3/(V/sub 98-x/Al/sub x/Ti/sub 2/) alloys with O ≤ x ≤ 80

International Nuclear Information System (INIS)

Das Gupta, A.; Horton, J.A.

1985-01-01

The sequence of disordering transformation processes in the A/sub 3/B type alloy series (Ni/sub 70/Fe/sub 30/)/sub 3/(V/sub 98-x/Al/sub x/Ti/sub 2/), currently under development for high-temperature structural applications, was studied by differential scanning calorimetry (DSC), x-ray diffraction, optical microscopy, and transmission electron microscopy (TEM). Results of DSC show that in all alloys there are two endothermic stages of phase transformation from the ordered to the disordered state. With increasing chi, the disordering transition temperature, T/sub c/, reaches a maximum --1000 0 C at chi ≅ 50 and then decreases. Interrupted heating, followed by water quenching, was used to characterize the crystal structure and the microstructure of the intermediate phases. For the x = 20 alloy, TEM observations showed ordered regions of DO/sub 22/ phase in a matrix of disordered fcc (Al) phase at intermediate temperatures. The ordered domains transformed morphologically into cuboid like regions at higher temperatures. From a combined study by all the techniques, the authors conclude that in alloy with x between 0 and 20, the sequence of phase transformations from heating is: DO/sub 2/ → DO/sub 22/ + Al → Al, whereas in alloys with x > 40, the major sequence is Ll/sub 2/ + B/sub 2/ → Ll/sub 2/ + Al → Al

[Carbon sequestration status of forest ecosystems in Ningxia Hui Autonomous Region].

Science.gov (United States)

Gao, Yang; Jin, Jing-Wei; Cheng, Ji-Min; Su, Ji-Shuai; Zhu, Ren-Bin; Ma, Zheng-Rui; Liu, Wei

2014-03-01

Based on the data of Ningxia Hui Autonomous Region forest resources inventory, field investigation and laboratory analysis, this paper studied the carbon sequestration status of forest ecosystems in Ningxia region, estimated the carbon density and storage of forest ecosystems, and analyzed their spatial distribution characteristics. The results showed that the biomass of each forest vegetation component was in the order of arbor layer (46.64 Mg x hm(-2)) > litterfall layer (7.34 Mg x hm(-2)) > fine root layer (6.67 Mg x hm(-2)) > shrub-grass layer (0.73 Mg x hm(-2)). Spruce (115.43 Mg x hm(-2)) and Pinus tabuliformis (94.55 Mg x hm(-2)) had higher vegetation biomasses per unit area than other tree species. Over-mature forest had the highest arbor carbon density among the forests with different ages. However, the young forest had the highest arbor carbon storage (1.90 Tg C) due to its widest planted area. Overall, the average carbon density of forest ecosystems in Ningxia region was 265.74 Mg C x hm(-2), and the carbon storage was 43.54 Tg C. Carbon density and storage of vegetation were 27.24 Mg C x hm(-2) and 4.46 Tg C, respectively. Carbon storage in the soil was 8.76 times of that in the vegetation. In the southern part of Ningxia region, the forest carbon storage was higher than in the northern part, where the low C storage was mainly related to the small forest area and young forest age structure. With the improvement of forest age structure and the further implementation of forestry ecoengineering, the forest ecosystems in Ningxia region would achieve a huge carbon sequestration potential.

X-ray-induced DNA double-strand breaks after angiographic examinations of different anatomic regions; Strahleninduzierte DNA-Doppelstrangbrueche nach Angiografien verschiedener Koerperregionen

Energy Technology Data Exchange (ETDEWEB)

Kuefner, M.A.; Schwab, S.A.; Azoulay, S.; Heckmann, M.; Heinrich, M.C.; Uder, M. [Universitaetsklinikum Erlangen (Germany). Radiologisches Inst.; Grudzenski, S.; Lobrich, M. [Technische Univ. Darmstadt (Germany). Strahlenbiologie und DNA-Reparatur

2009-04-15

Purpose: The aim of this study was to investigate DNA double-strand breaks (DSBs) in blood lymphocytes as markers of the biological radiation effects in angiography patients. Materials and Methods: The method is based on the phosphorylation of the histone variant H 2AX ({gamma}-H2AX) after formation of DSBs. Blood samples were collected before and up to 24 hours after exposure of 31 patients undergoing angiographies of different body regions. Blood lymphocytes were isolated, fixed, and stained with a specific {gamma}-H2AX antibody. Distinct foci representing DSBs were enumerated using fluorescence microscopy. Additional in-vitro experiments (10 - 100 mGy) were performed for evaluation of DBS repair. Results: 15 minutes after the end of fluoroscopy values between 0.01 and 1.50 DSBs per cell were obtained. The DNA damage level normalized to the dose area product was 0.099 (cardiac angiographies), 0.053 (abdominal angiographies), 0.023 (pelvic/leg angiographies) and 0.004 excess foci/cell/mGym{sup 2} (cerebrovascular angiographies). A linear correlation was found between {gamma}-H2AX foci levels and the dose area product (abdomen: R2 = 0.96; pelvis/legs: R2 = 0.71). In-vivo on average 46 % of DSBs disappeared within 1 hour and 70 % within 2.5 hours. Conclusion: {gamma}-H2AX immunofluorescence microscopy is a sensitive and reliable method for the determination of X-ray-induced DSBs during angiography. The DNA damage level depends on the dose, the exposed anatomic region, and the duration/fractionation of the X-ray exposure. (orig.)

Investigation of Optically Modified YBa2Cu3O7–x Films by Means of X-ray Microanalysis Technique

Directory of Open Access Journals (Sweden)

Artūras JUKNA

2014-06-01

Full Text Available This work reports on investigation of remnant oxygen content in optically-modified regions of 0.3-mm-thick YBa2Cu3O7–x films, patterned by a laser-writing technique in an inert ambient gas atmosphere at room temperature. A laser-treated region of weak superconductivity with dimensions depending on the size of a laser spot, laser power, and initial content of oxygen is characterized by a lower oxygen content, weaker critical magnetic field, and suppressed both the superconducting critical temperature and the critical current density, as compared to the laser untreated regions. Optically induced (cw-laser, 532-nm-wavelength heating strongly affects a non-uniform distribution of remnant oxygen content in the film, depending both on the optical power and beam’s scanning velocity. A level of oxygen depletion and the size of the oxygen-deficient region have been directly estimated from scanning-electron-microscope spectra with the X-ray microanalysis technique. The results of our measurements were compared with results extracted from electric measurements, assuming a correlation between the remnant oxygen content and the electric transport properties of oxygen-deficient YBa2Cu3O7–x films. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6323

X transport and its effect on H-mode and edge pedestal in tokamaks

International Nuclear Information System (INIS)

Chang, C.S.; Darrow, D.; White, R.; Lin, Z.; Lee, W.; Ku, S.H.; Weitzner, H.; Carlstrom, T.N.; Grassie, J.S. de

2001-01-01

A new classical non-ambipolar transport mechanism has been identified which can be a dominant source of strong Er and edge pedestal layer formation immediately inside the separatrix in a diverted tokamak. Due to vanishingly small poloidal B-field and grad-B drift toward x-point, plasma ions with small ν parallel in the X-region do not have confined single particle orbits. This leads to a non-ambipolar convective transport in the X-region (X-transport), either collisional or collisionless, inducing a strong negative Er-shear layer. The X-transport can provide basic understanding of many of the experimental observations. (author)

An X-linked homologue of the autosomal inprinted gene ZNF127 escapes X inactivation

Energy Technology Data Exchange (ETDEWEB)

Longstreet, M.; Nicholls, R.D.; Willard, H.F. [Case Western Reserve Univ., Cleveland, OH (United States)] [and others

1994-09-01

The ZNF127 gene has been shown to be subject to parental imprinting in both humans and the mouse and maps to within the Prader-Willi/Angelman Syndrome critical region on chromosome 15. We have cloned two X-linked related loci, one of which, ZNFXp is a transcribed gene while the other, ZNFXq, is an untranscribed pseudogene. ZNFXp is 83.6% identical to ZNFXq and 65.4% identical to ZNF127 over 1.4 kb of open reading frame they share in common, Like ZNF127, the predicted protein sequence of ZNFXp contains a C{sub 3}HC{sub 4} zinc finger domain and C{sub 3}H zinc finger-like motifs. Whereas ZNF127 has three C{sub 3}H motifs, ZNFXp has four. A strong CpG island is located within 1 kb 5{prime} of the predicted amino terminus of ZNFXp. Expression of ZNFXp has been detected from mouse/human somatic cell hybrids containing either an active (n=2) or an inactive (n=4) chromosome, and thus escapes X inactivation. Probes made from the 3{prime} UTR of ZNFXp detect a number of related loci in both human and murine DNA, none of which is the ZNF127 locus on chromosome 15. None of the detectable murine bands shows dosage differences between males and females as would be expected for X-linked loci. This raises the possibility that ZNFXp inserted into the human X chromosome after its divergence from a common ancestor with the murine X. We have mapped ZNFXp to Xp11.4 by Southern blotting and PCR of hybrid DNAs and by fluorescence in situ hybridization (FISH). ZNFXq maps within the X Inactivation Center (XIC) region on Xq13.2, approximately 300 kb distal to the XIST gene. We find it intriguing, and perhaps significant, that two members of this gene family are subject to epigenetic regulation -- one autosomal imprinting, and the other escape from X inactivation. These results could imply an evolutionary and mechanistic relationship between these two processes.

Comparison of nonflare solar soft x ray flux with 10.7-cm radio flux

International Nuclear Information System (INIS)

Donnelly, R.F.

1982-01-01

The similarities and differences of the nonflare solar 1- to 8-A X ray flux and the daily 10.7-cm Ottawa solar radio flux are examined. The radio flux is shown to be much less sensitive than the soft X ray flux on the average to the coronal emission of active regions located near or beyond the solar chromospheric limb relative to regions near the center of the solar disk. This is caused by the solar soft X ray emission's being optically thin while much of the 10.7-cm active region emission is from optical depths of tauapprox.1. The radio flux includes a large quiet sun flux which is emitted mostly from the tenuous chromosphere-corona transition region (Tapprox.10 4 --10 6 0 K) and partly from the cooler portions of the quiet corona Tapprox.1.5 x 10 6 0 K. Conversely, the solar soft X ray flux has a very small quiet sun component

High-Sensitive Two-Layer Photoresistors Based on p-Cd x Hg1-x Te with a Converted Near-Surface Layer

Science.gov (United States)

Ismailov, N. D.; Talipov, N. Kh.; Voitsekhovskii, A. V.

2018-04-01

The results of an experimental study of photoelectric characteristics of two-layer photoresistors based on p-Cd x Hg1-x Te (x = 0.24-0.28) with a thin near-surface layer of n-type obtained by treatment in atmospheric gas plasma are presented. It is shown that the presence of a potential barrier between the p- and n-regions causes high photosensitivity and speed of operation of such photoresistors at T = 77 K

High-Sensitive Two-Layer Photoresistors Based on p-Cd x Hg1- x Te with a Converted Near-Surface Layer

Science.gov (United States)

Ismailov, N. D.; Talipov, N. Kh.; Voitsekhovskii, A. V.

2018-04-01

The results of an experimental study of photoelectric characteristics of two-layer photoresistors based on p-Cd x Hg1- x Te (x = 0.24-0.28) with a thin near-surface layer of n-type obtained by treatment in atmospheric gas plasma are presented. It is shown that the presence of a potential barrier between the p- and n-regions causes high photosensitivity and speed of operation of such photoresistors at T = 77 K

Method of producing a pseudo-color photograph with X-rays

International Nuclear Information System (INIS)

Tajima, Mataichi.

1965-01-01

Conventional black and white X-ray photography cannot simultaneously produce an image on photographic film of a subject having regions of high and low X-ray absorption due to the limitation of photographic density range, gradation and exposure tolerance. This invention records both regions as images of different colors on the same color photographic film. According to a method of this invention for making an X-ray pseudo-color photograph, the subject is directly irradiated by an X-ray beam emergent from an X-ray beam generator, and an X-ray permeation image of the subject is converted into and displayed as a visible light image by means of a fluorescent screen. In one aspect of this invention, there is used a color photographic film which has at least two kinds of sensitive and coloring layers exhibiting the same sensitivity. During the period in which the visible image is displayed, the film is exposed to the visible light in such a way that at least two color filters differing in color and density are successively interposed between the film and the fluorescent screen. In another aspect, a color photographic film is employed having at least two kinds of sensitive and coloring layers exhibiting different sensitivities. During the period in which the visible image is displayed, the film is exposed to visible light by sequentially interposing at least two color filters of different color but of equal density. In this manner, regions comparatively low in X-ray absorption, such as the lungs, and regions comparatively high in absorption, such as the heart, appear as, for example, a blue image and a red image on the color photographic film, respectively. (Takasuka, S.)

Real-Space Bonding Indicator Analysis of the Donor-Acceptor Complexes X3BNY3, X3AlNY3, X3BPY3, and X3AlPY3 (X, Y = H, Me, Cl).

Science.gov (United States)

Mebs, Stefan; Beckmann, Jens

2017-10-12

Calculations of real-space bonding indicators (RSBI) derived from Atoms-In-Molecules (AIM), Electron Localizability Indicator (ELI-D), Non-Covalent Interactions index (NCI), and Density Overlap Regions Indicator (DORI) toolkits for a set of 36 donor-acceptor complexes X 3 BNY 3 (1, 1a-1h), X 3 AlNY 3 (2, 2a-2h), X 3 BPY 3 (3, 3a-3h), and X 3 AlPY 3 (4, 4a-4h) reveal that the donor-acceptor bonds comprise covalent and ionic interactions in varying extents (X = Y = H for 1-4; X = H, Y = Me for 1a-4a; X = H, Y = Cl for 1b-4b; X = Me, Y = H for 1c-4c; X, Y = Me for 1d-4d; X = Me, Y = Cl for 1e-4e; X = Cl, Y = H for 1f-4f; X = Cl, Y = Me for 1g-4g; X, Y = Cl for 1h-4h). The phosphinoboranes X 3 BPY 3 (3, 3a-3h) in general and Cl 3 BPMe 3 (3f) in particular show the largest covalent contributions and the least ionic contributions. The aminoalanes X 3 AlNY 3 (2, 2a-2h) in general and Me 3 AlNCl 3 (2e) in particular show the least covalent contributions and the largest ionic contributions. The aminoboranes X 3 BNY 3 (1, 1a-1h) and the phosphinoalanes X 3 AlPY 3 (4, 4a-4h) are midway between phosphinoboranes and aminoalanes. The degree of covalency and ionicity correlates with the electronegativity difference BP (ΔEN = 0.15) < AlP (ΔEN = 0.58) < BN (ΔEN = 1.00) < AlN (ΔEN = 1.43) and a previously published energy decomposition analysis (EDA). To illustrate the importance of both contributions in Lewis formula representations, two resonance formulas should be given for all compounds, namely, the canonical form with formal charges denoting covalency and the arrow notation pointing from the donor to the acceptor atom to emphasis ionicity. If the Lewis formula mainly serves to show the atomic connectivity, the most significant should be shown. Thus, it is legitimate to present aminoalanes using arrows; however, for phosphinoboranes the canonical form with formal charges is more appropriate.

The (AgInSe{sub 2}){sub 1-x}(VSe){sub x} system (0{<=}x{<=}0.5): X-ray diffraction and differential thermal analysis measurements

Energy Technology Data Exchange (ETDEWEB)

Duran, S.; Grima, P.; Quintero, M.; Ruiz, J. [Centro de Estudio en Semiconductores (C.E.S.), Dpto. Fisica, Fac. Ciencias, Universidad de Los Andes, Merida (Venezuela); Munoz, M. [Centro de Estudio en Semiconductores (C.E.S.), Dpto. Fisica, Fac. Ciencias, Universidad de Los Andes, Merida (Venezuela); Ceballos, L. [Laboratorio de Cristalografia, Dpto. Quimica, Fac. Ciencias, Universidad de Los Andes, Merida (Venezuela); Briceno, J.M. [Laboratorio de Analisis Quimico y Estructural (LAQUEM), Dpto. Fisica, Fac. Ciencias, Universidad de Los Andes, Merida (Venezuela); Romero, H. [Laboratorio de Magnetismo de Solidos, Dpto. Fisica, Fac. Ciencias, Universidad de Los Andes, Merida (Venezuela)

2005-08-01

Polycrystalline samples of the (AgInSe{sub 2}){sub 1-x}(VSe){sub x} system were prepared by the melt and anneal method. The anneal temperature was 900 K and the anneal time one month. The step composition was 0.1 and the weight of each sample approximately 1 g. Additionally, the composition x=1/3 was also prepared, since these alloys have been reported as electronic, i.e. definite compounds exist in the diagram at precise values of composition, one of them x=1/3. The stoichiometric relation of the samples was investigated by SEM technique. The experimental values, in average, are very close to the nominal values, all of them lying inside the interval of the experimental error ({+-}5%). X-Ray Diffraction (XRD) and Differential Thermal Analysis (DTA) techniques were used for characterization of the alloy samples. Guinier photographs were obtained for all the samples and unit cell parameters were calculated using the available software for indexation. The diffraction patterns show sharp lines indicating good thermal equilibrium of the samples. Transition temperatures obtained from DTA measurements were manually obtained from the T vs. T graph with the criteria that the transition occurs at the intersection of the base line with the slope of the thermal transition peak, as usually. From the analysis of the experimental results it was observed that the solid solubility of VSe in AgInSe{sub 2} is approximately 20%, i.e. the single-phase region exists in the composition range 0{<=}x<0.2, whereas for x>0.2 at least two phases coexist. A schematic T-x phase diagram is proposed. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Construction of physical maps for the sex-specific regions of papaya sex chromosomes

Directory of Open Access Journals (Sweden)

Na Jong-Kuk

2012-05-01

Full Text Available Abstract Background Papaya is a major fruit crop in tropical and subtropical regions worldwide. It is trioecious with three sex forms: male, female, and hermaphrodite. Sex determination is controlled by a pair of nascent sex chromosomes with two slightly different Y chromosomes, Y for male and Yh for hermaphrodite. The sex chromosome genotypes are XY (male, XYh (hermaphrodite, and XX (female. The papaya hermaphrodite-specific Yh chromosome region (HSY is pericentromeric and heterochromatic. Physical mapping of HSY and its X counterpart is essential for sequencing these regions and uncovering the early events of sex chromosome evolution and to identify the sex determination genes for crop improvement. Results A reiterate chromosome walking strategy was applied to construct the two physical maps with three bacterial artificial chromosome (BAC libraries. The HSY physical map consists of 68 overlapped BACs on the minimum tiling path, and covers all four HSY-specific Knobs. One gap remained in the region of Knob 1, the only knob structure shared between HSY and X, due to the lack of HSY-specific sequences. This gap was filled on the physical map of the HSY corresponding region in the X chromosome. The X physical map consists of 44 BACs on the minimum tiling path with one gap remaining in the middle, due to the nature of highly repetitive sequences. This gap was filled on the HSY physical map. The borders of the non-recombining HSY were defined genetically by fine mapping using 1460 F2 individuals. The genetically defined HSY spanned approximately 8.5 Mb, whereas its X counterpart extended about 5.4 Mb including a 900 Kb region containing the Knob 1 shared by the HSY and X. The 8.5 Mb HSY corresponds to 4.5 Mb of its X counterpart, showing 4 Mb (89% DNA sequence expansion. Conclusion The 89% increase of DNA sequence in HSY indicates rapid expansion of the Yh chromosome after genetic recombination was suppressed 2–3 million years ago. The

In vivo brain anatomy of adult males with Fragile X syndrome: an MRI study.

Science.gov (United States)

Hallahan, Brian P; Craig, Michael C; Toal, Fiona; Daly, Eileen M; Moore, Caroline J; Ambikapathy, Anita; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

2011-01-01

Fragile X Syndrome (FraX) is caused by the expansion of a single trinucleotide gene sequence (CGG) on the X chromosome, and is a leading cause of learning disability (mental retardation) worldwide. Relatively few studies, however, have examined the neuroanatomical abnormalities associated with FraX. Of those that are available many included mixed gender populations, combined FraX children and adults into one sample, and employed manual tracing techniques which measures bulk volume of particular regions. Hence, there is relatively little information on differences in grey and white matter content across whole brain. We employed magnetic resonance imaging to investigate brain anatomy in 17 adult males with FraX and 18 healthy controls that did not differ significantly in age. Data were analysed using stereology and VBM to compare (respectively) regional brain bulk volume, and localised grey/white matter content. Using stereology we found that FraX males had a significant increase in bulk volume bilaterally of the caudate nucleus and parietal lobes and of the right brainstem, but a significant decrease in volume of the left frontal lobe. Our complimentary VBM analysis revealed an increased volume of grey matter in fronto-striatal regions (including bilaterally in the caudate nucleus), and increased white matter in regions extending from the brainstem to the parahippocampal gyrus, and from the left cingulate cortex extending into the corpus callosum. People with FraX have regionally specific differences in brain anatomy from healthy controls with enlargement of the caudate nuclei that persists into adulthood. Copyright © 2010 Elsevier Inc. All rights reserved.

In vivo brain anatomy of adult males with Fragile X syndrome: an MRI study.

LENUS (Irish Health Repository)

Hallahan, Brian P

2011-01-01

Fragile X Syndrome (FraX) is caused by the expansion of a single trinucleotide gene sequence (CGG) on the X chromosome, and is a leading cause of learning disability (mental retardation) worldwide. Relatively few studies, however, have examined the neuroanatomical abnormalities associated with FraX. Of those that are available many included mixed gender populations, combined FraX children and adults into one sample, and employed manual tracing techniques which measures bulk volume of particular regions. Hence, there is relatively little information on differences in grey and white matter content across whole brain. We employed magnetic resonance imaging to investigate brain anatomy in 17 adult males with FraX and 18 healthy controls that did not differ significantly in age. Data were analysed using stereology and VBM to compare (respectively) regional brain bulk volume, and localised grey\\/white matter content. Using stereology we found that FraX males had a significant increase in bulk volume bilaterally of the caudate nucleus and parietal lobes and of the right brainstem, but a significant decrease in volume of the left frontal lobe. Our complimentary VBM analysis revealed an increased volume of grey matter in fronto-striatal regions (including bilaterally in the caudate nucleus), and increased white matter in regions extending from the brainstem to the parahippocampal gyrus, and from the left cingulate cortex extending into the corpus callosum. People with FraX have regionally specific differences in brain anatomy from healthy controls with enlargement of the caudate nuclei that persists into adulthood.

Spatial power-spectra from Yohkoh soft X-ray images

Science.gov (United States)

Martens, Petrus C. H.; Gomez, Daniel O.

1992-01-01

We analyze three sequences of images from active regions, and a full disk image obtained by Yohkoh's Soft X-ray Telescope. Two sequences are from a region at center disk observed through different filters, and one sequence is from the limb. After Fourier-transforming the X-ray intensity of the images we find nearly isotropic power-spectra with an azimuthally integrated slope of -2.1 for the center disk, and -2.8 for the limb images. The full-disk picture yields a spectrum of -2.4. These results are different from the active region spectra obtained with the Normal Incidence X-ray Telescope which have a slope of the order of -3.0, and we ascribe this to the difference in temperature response between the instruments. However, both the SXT and NIXT results are consistent with coronal heating as the end result of a downward quasistatic cascade (in lengthscales) of free magnetic energy in the corona, driven by footpoint motions in the photosphere.

On the periodic orbits of the Third-order differential equation x ' ' '- x ' ' x'- x= F(x,x',x ' ')

OpenAIRE

Llibre, Jaume

2013-01-01

Agraïments: The second author is partially supported by CAPES/MECD-DGU 222/2010 Brazil and Spain In this paper we study the periodic orbits of the third-order differential equation x''' − µx'' + x' − µx = εF(x, x', x''), where ε is a small parameter and the function F is of class C2.

X-ray Emission Line Spectroscopy of Nearby Galaxies

Science.gov (United States)

Wang, Daniel

What are the origins of the diffuse soft X-ray emission from non-AGN galaxies? Preliminary analysis of XMM-Newton RGS spectra shows that a substantial fraction of the emission cannot arise from optically-thin thermal plasma, as commonly assumed, and may originate in charge exchange at the interface with neutral gas. We request the support for a comprehensive observing, data analysis, and modeling program to spectroscopically determine the origins of the emission. First, we will use our scheduled XMM-Newton AO-10 368 ks observations of the nearest compact elliptical galaxy M32 to obtain the first spectroscopic calibration of the cumulative soft X-ray emission from the old stellar population and will develop a spectral model for the charge exchange, as well as analysis tools to measure the spatial and kinematic properties of the X-ray line- emitting plasma. Second, we will characterize the truly diffuse emission from the hot plasma and/or its interplay with the neutral gas in a sample of galactic spheroids and active star forming/starburst regions in nearby galaxies observed by XMM-Newton. In particular, we will map out the spatial distributions of key emission lines and measure (or tightly constrain) the kinematics of hot plasma outflows for a few X-ray-emitting regions with high-quality RGS data. For galaxies with insufficient counting statistics in individual emission lines, we will conduct a spectral stacking analysis to constrain the average properties of the X-ray-emitting plasma. We will use the results of these X-ray spectroscopic analyses, together with complementary X-ray CCD imaging/spectral data and observations in other wavelength bands, to test the models of the emission. In addition to the charge exchange, alternative scenarios such as resonance scattering and relic AGN photo-ionization will also be examined for suitable regions. These studies are important to the understanding of the relationship between the diffuse soft X-ray emission and various

Relationships among arteriolar, regional, and whole organ blood flow in cremaster muscle

International Nuclear Information System (INIS)

Proctor, K.G.; Busija, D.W.

1985-01-01

The relationship between microvessel and tissue blood flow (BF) was determined with two different techniques during changes in local vasomotor tone in the rat cremaster muscle. Whole organ and regional BF were measured with the radioactive microsphere technique (BFms) and compared with values calculated in individual arterioles (BFc) using the dual-slit cross-correlation technique. In the muscle prepared for microcirculatory observation (i.e., dissected, surgically divided into a flattened sheet, and covered with clear plastic), resting BFms was 43 +/- 3 ml X min-1 X 100 g-1, which was significantly higher than paired BFms in the contralateral undisturbed muscle (24 +/- 7 ml X min-1 X 100 g-1). Over a range in vasomotor tone, regional BFms to the edge of the tissue, which was exposed to the trauma of the surgery, was 56 +/- 7 ml X min-1 X 100 g-1 compared with 38 +/- 5 in the less traumatized center region, a significant difference of 79 +/- 31%. There was no linear relationship between arteriolar BFc and BFms. The correlation was not improved if the factors of vessel size, vasomotor tone, animal size, or muscle size were considered. Changes in arteriolar BFc (y) overestimated changes in total tissue BFms (x) by a factor of 2 (y = 2.01x - 0.6; r = 0.86), but changes in arteriolar BFc were proportional to changes in BFms if only the center region (x) of the tissue was considered (y = 1.08x - 0.1; r = 0.84). The general implication from these results is that factors that influence perfusion heterogeneity, such as surgical trauma, should be carefully considered when correlating macro- and microcirculatory measurements of BF

Phylogeography of haplotypes of five microsatellites located in a low-recombination region of the X chromosome: studies worldwide and in Brazilian populations.

Science.gov (United States)

Pereira, Rinaldo Wellerson; Pena, Sérgio D J

2006-01-01

We studied five microsatellites (DXS995, DXS8076, DXS8114, DXS1002 and DXS1050) located in a region of very low recombination rate in the long arm of the human X chromosome (Xq13.3-Xq21.3). No recombination was seen in 291 meioses in CEPH families. To test whether haplotypes composed of the five microsatellites could differentiate among distinct human continental populations, we studied an international panel containing 72 males from Africa, Europe, Asia and the America. Haplotypic diversity was very high within these groups and no haplotypes were shared among them. This led to the hope that we might be able to identify continent-specific lineages. However, in a median joining network there was no clear discrimination of the different continental groups. We then tested whether we could identify X chromosomal lineages from different continental origins in Brazilians. We typed 180 white Brazilians from four different geographical regions and examined their proportions of haplotype sharing with Africans, Asians, Europeans and Amerindians. No phylogeographical patterns emerged from the data. Moreover, there were several instances of the same haplotype being shared by many (and in one instance all) groups, suggesting that recombination might be occurring. We thus studied pairwise the level of linkage disequilibrium (LD) between the microsatellites. No detectable linkage disequilibrium between the most external loci DXS995 and DXS1050 was observed. Thus, even though recombination may be absent on short time spans, as seen in the CEPH pedigrees, on a long term basis it occurs often enough to dissipate all linkage disequilibrium. On the other hand, we observed very strong linkage disequilibrium between the pairs DXS995/DXS8076 and DXS1002/DXS8114, raising the possibility of resequencing the segment between them to identify single nucleotide polymorphisms (SNPs) in their intervals. The combination of X-linked microsatellites and SNPs in strong linkage disequilibrium might

Laser plasma X-ray for non-destructive inspection

International Nuclear Information System (INIS)

Yagi, T.; Kusama, H.

1995-01-01

External electric field is applied to the laser produced plasma, and its found that plasma shape in soft X-ray region is changed due to the penetrating electric field. The plasma emits strong hard X-ray, which can be used as a compact light source for non-destructive inspection. (author)

Magnetic exchange coupling in amorphous Fe80-xDy xB20 alloys

International Nuclear Information System (INIS)

Annouar, F.; Lassri, H.; Ayadi, M.; Omri, M.; Lassri, M.; Krishnan, R.

2005-01-01

Amorphous Fe 80-x Dy x B 20 alloys have been prepared by melt spinning and their magnetic properties have been studied. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co-Co and Dy-Co atom pairs have been evaluated. High-field magnetization studies on samples with stoichiometry close to that of a compensated ferrimagnet show a magnetic behavior that is characteristic of a non-collinear magnetic structure of the Dy and Fe sublattices. The region of the canted moments can be described by a phase diagram in the H-T plane

Soft X-ray spectrographs for solar observations

Science.gov (United States)

Bruner, M. E.

1988-01-01

Recent advances in soft X-ray spectrometery are reviewed, with emphasis on techniques for studying the windowless region from roughly 1-100 A. Recent technological developments considered include multilayer mirrors, large-format CCD detectors which are sensitive to X-rays, position-sensitive photon counting detectors, new kinds of X-ray films, and optical systems based on gratings with nonuniform ruling spacings. Improvements in the extent and accuracy of the atomic physics data sets on which the analysis of spectroscopic observatons depend are also discussed.

Observation of the transition from diffusive regime to ballistic regime of the 2DEG transport property in Al xGa1-xN/GaN heterostructures

International Nuclear Information System (INIS)

Han, K.; Shen, B.; Tang, N.; Tang, Y.Q.; He, X.W.; Qin, Z.X.; Yang, Z.J.; Zhang, G.Y.; Lin, T.; Zhu, B.; Zhou, W.Z.; Chu, J.H.

2007-01-01

Electron-electron interaction effect of the two-dimensional electron gas (2DEG) in Al x Ga 1-x N/GaN heterostructures has been investigated by means of magnetotransport measurements at low temperatures. From the temperature dependence of the longitudinal conductivity of the heterostructures, a clear transition region has been observed. Based on the theoretical analysis, we conclude that this region corresponds to the transition from the diffusive regime to the ballistic regime of the 2DEG transport property. The interaction constant is determined to be -0.423, which is consistent with the theoretical prediction. However, the critical temperature for the transition, which is 8 K in Al x Ga 1-x N/GaN heterostructures, is much higher than the theoretical prediction

Proton structure functions at small x

International Nuclear Information System (INIS)

Hentschinski, Martin

2015-01-01

Proton structure functions are measured in electron-proton collision through inelastic scattering of virtual photons with virtuality Q on protons; x denotes the momentum fraction carried by the struck parton. Proton structure functions are currently described with excellent accuracy in terms of scale dependent parton distribution functions, defined in terms of collinear factorization and DGLAP evolution in Q. With decreasing x however, parton densities increase and are ultimately expected to saturate. In this regime DGLAP evolution will finally break down and non-linear evolution equations w.r.t x are expected to take over. In the first part of the talk we present recent result on an implementation of physical DGLAP evolution. Unlike the conventional description in terms of parton distribution functions, the former describes directly the Q dependence of the measured structure functions. It is therefore physical insensitive to factorization scheme and scale ambiguities. It therefore provides a more stringent test of DGLAP evolution and eases the manifestation of (non-linear) small x effects. It however requires a precise measurement of both structure functions F 2 and F L , which will be only possible at future facilities, such as an Electron Ion Collider. In the second part we present a recent analysis of the small x region of the combined HERA data on the structure function F 2 . We demonstrate that (linear) next-to-leading order BFKL evolution describes the effective Pomeron intercept, determined from the combined HERA data, once a resummation of collinear enhanced terms is included and the renormalization scale is fixed using the BLM optimal scale setting procedure. We also provide a detailed description of the Q and x dependence of the full structure functions F 2 in the small x region, as measured at HERA. Predictions for the structure function F L are found to be in agreement with the existing HERA data. (paper)

Compton backscattered collmated X-ray source

Science.gov (United States)

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collimated x-ray source

Science.gov (United States)

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Open magnetic fields in active regions

International Nuclear Information System (INIS)

Svestka, Z.; Solodyna, C.V.; Levine, R.H.

1977-01-01

Soft X-ray observations confirm that some of the dark gaps seen between interconnecting loops and inner cores of active regions may be loci of open fields, as it has been predicted by global potential extrapolation of photospheric magnetic fields. It seems that the field lines may open only in a later state of the active region development. (Auth.)

X-RAY OUTFLOWS AND SUPER-EDDINGTON ACCRETION IN THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1

International Nuclear Information System (INIS)

Walton, D. J.; Harrison, F. A.; Miller, J. M.; Reis, R. C.; Fabian, A. C.; Roberts, T. P.; Middleton, M. J.

2013-01-01

Studies of X-ray continuum emission and flux variability have not conclusively revealed the nature of ultraluminous X-ray sources (ULXs) at the high-luminosity end of the distribution (those with L X ≥ 10 40 erg s –1 ). These are of particular interest because the luminosity requires either super-Eddington accretion onto a black hole of mass ∼10 M ☉ or more standard accretion onto an intermediate-mass black hole. Super-Eddington accretion models predict strong outflowing winds, making atomic absorption lines a key diagnostic of the nature of extreme ULXs. To search for such features, we have undertaken a long, 500 ks observing campaign on Holmberg IX X-1 with Suzaku. This is the most sensitive data set in the iron K bandpass for a bright, isolated ULX to date, yet we find no statistically significant atomic features in either emission or absorption; any undetected narrow features must have equivalent widths less than 15-20 eV at 99% confidence. These limits are far below the ∼>150 eV lines expected if observed trends between mass inflow and outflow rates extend into the super-Eddington regime and in fact rule out the line strengths observed from disk winds in a variety of sub-Eddington black holes. We therefore cannot be viewing the central regions of Holmberg IX X-1 through any substantial column of material, ruling out models of spherical super-Eddington accretion. If Holmberg IX X-1 is a super-Eddington source, any associated outflow must have an anisotropic geometry. Finally, the lack of iron emission suggests that the stellar companion cannot be launching a strong wind and that Holmberg IX X-1 must primarily accrete via Roche-lobe overflow

Substance accretion onto supermassive black holes and X radiation of active galaxy nuclei

International Nuclear Information System (INIS)

Zentsova, A.S.

1980-01-01

The X-ray radiation of quasars and Seyfert galaxies is explained on the ground of the two-temperature model of the disk accretion onto a supermassive black hole. The inner region of the disk is optically thin to absorption, gas-pressure dominated and the electron temperature is approximately 5x10 8 K and ion temperature is approximately 10 3 times higher. X radiation is produced by inverse Compton scatetring of soft radiation in the inner region of the disk. The source of soft radiation is the outer region of the disk. This model predicts a power spectrum of the radiation from 1 to 60 keV with the index γ=1, the latter approaches to a mean spectral index of X radiation of active galaxy nuclei [ru

Near infrared fluorescence and energy transfer in Ce/Nd Co-doped Ca{sub x}Sr{sub 1-x}S

Energy Technology Data Exchange (ETDEWEB)

Meng Jianxin, E-mail: tmjx@jnu.edu.c [Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Department of Chemistry, Jinan University, Guangzhou 510632 (China); Wan Wenjiao; Fan Lili; Yang Chuangtao; Chen Qingqing [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Cao Liwei; Man Shiqing [Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China)

2011-01-15

Novel near infrared (NIR) phosphors Ca{sub x}Sr{sub 1-x}S:Ce{sup 3+},Nd{sup 3+} were synthesized by a solid state reaction. The NIR emission was realized through an efficient absorption by the allowed 4f-5d transition of Ce{sup 3+} and efficient energy transfer to Nd{sup 3+} via well-matched energy levels. Ce{sup 3+} and Nd{sup 3+} content in CaS/SrS was optimized. It was found that CaS:Ce{sup 3+},Nd{sup 3+} gave much stronger NIR emission than that of SrS:Ce{sup 3+},Nd{sup 3+}. Further studies on Ca{sub x}Sr{sub 1-x}S:Ce{sup 3+},Nd{sup 3+} indicated that both visible emission of Ce{sup 3+} and NIR emission of Nd{sup 3+} were observably affected by Ca/Sr ratio. The energy transfer efficiency, which can be estimated from fluorescence lifetime of Ce{sup 3+}, increased from 52% to 74% for the Ca{sub x}Sr{sub 1-x}S:Ce{sup 3+},Nd{sup 3+} (x=0 to 1) series, accompanied with a shift of maximal emission wavelength of Ce{sup 3+} from 482 to 505 nm. The results showed that overlap between emission spectrum of Ce{sup 3+} and excitation spectrum of Nd{sup 3+} plays an important role in the energy transfer efficiency, and Ce{sup 3+} emitting in green or blue-greenish region sensitized the Nd{sup 3+} NIR fluorescence emission more efficiently than that in blue region.

Urological complications after x-ray-therapy and their treatment

Energy Technology Data Exchange (ETDEWEB)

Lichtenauer, P; Nentwig, N; Lobsien, I [Medizinische Hochschule Luebeck (F.R. Germany). Chirurgische Klinik und Poliklinik

1974-10-01

Early reactions on X-ray-therapy in the bladder region usually begin with pain. Sterile irritations are reversible under symptomatic therapy. Real bladder infections should be dealt with according to antibiogram intensively and for a long time before the X-ray-stress is continued. Late reactions on X-ray-therapy mostly are organised and irreversible. The different manifestations are referred to and the respective therapy is recommended.

Soft x-ray streak cameras

International Nuclear Information System (INIS)

Stradling, G.L.

1988-01-01

This paper is a discussion of the development and of the current state of the art in picosecond soft x-ray streak camera technology. Accomplishments from a number of institutions are discussed. X-ray streak cameras vary from standard visible streak camera designs in the use of an x-ray transmitting window and an x-ray sensitive photocathode. The spectral sensitivity range of these instruments includes portions of the near UV and extends from the subkilovolt x- ray region to several tens of kilovolts. Attendant challenges encountered in the design and use of x-ray streak cameras include the accommodation of high-voltage and vacuum requirements, as well as manipulation of a photocathode structure which is often fragile. The x-ray transmitting window is generally too fragile to withstand atmospheric pressure, necessitating active vacuum pumping and a vacuum line of sight to the x-ray signal source. Because of the difficulty of manipulating x-ray beams with conventional optics, as is done with visible light, the size of the photocathode sensing area, access to the front of the tube, the ability to insert the streak tube into a vacuum chamber and the capability to trigger the sweep with very short internal delay times are issues uniquely relevant to x-ray streak camera use. The physics of electron imaging may place more stringent limitations on the temporal and spatial resolution obtainable with x-ray photocathodes than with the visible counterpart. Other issues which are common to the entire streak camera community also concern the x-ray streak camera users and manufacturers

Mössbauer study on a two-dimensional random mixture with competing spin anisotropies K2Ni1- x Fe x F4

Science.gov (United States)

Ito, A.; Anma, T.

1987-03-01

Mössbauer measurements have been made on a two-dimensional (2D) random mixture K2Ni1- x Fe x F4 with competing spin anisotropies. The concentration versus temperature phase diagram predicted by Oguchi and Ishikawa for mixed systems with competition between orthorhombic anisotropies has been shown to exist in K2Ni1- x Fe x F4. The coexistence of two kinds of Mössbauer spectra is seen in the transition regions, and is believed to be an intrinsic property of this system.

Tissue chemical analysis with muonic X-rays

International Nuclear Information System (INIS)

Hutson, R.L.; Reidy, J.J.; Springer, K.; Daniel, H.; Knowles, H.B.

1976-01-01

The stopped muon channel at the Clinton P. Anderson Meson Physics Facility (LAMPF) was used as a source of muons for studying the elemental composition of tissue with muonic X rays. The X ray spectra from several types of tissue were used to determine the amounts of carbon, nitrogen, and oxygen present. These determinations agree with the results of more conventional chemical analysis. The results show that muonic X rays offer a non-invasive technique for determining the amounts of the more abundant elements present in selected regions of the body. (orig.) [de

New insights into the X-ray properties of nearby barred spiral galaxy NGC 1672

Science.gov (United States)

Jenkins, L. P.; Brnadt, W. N.; Colbert, E. J. M.; Levan, A. J.; Roberts, T. P.; Ward, M. J.; Zezas, A.

2008-02-01

We present some preliminary results from new Chandra and XMM-Newton X-ray observations of the nearby barred spiral galaxy NGC1672. It shows dramatic nuclear and extra-nuclear star formation activity, including starburst regions located near each end of its strong bar, both of which host ultraluminous X-ray sources (ULXs). With the new high-spatial-resolution Chandra imaging, we show for the first time that NGC1672 possesses a faint ($L(X)~10^39 erg/s), hard central X-ray source surrounded by an X-ray bright circumnuclear starburst ring that dominates the X-ray emission in the region. The central source may represent low-level AGN activity, or alternatively the emission from X-ray binaries associated with star-formation in the nucleus.

Construction of a YAC contig and STS map spanning 2.5 Mbp in Xq25, the critical region for the X-linked lymphoproliferative (XLP) gene

Energy Technology Data Exchange (ETDEWEB)

Lanyi, A.; Li, B.F.; Li, S. [Univ. of Nebraska Medical Center, Omaha, NE (United States)] [and others

1994-09-01

X-linked lymphoproliferative disease (XLP) is characterized by a marked vulnerability in Epstein-Barr virus (EBV) infection. Infection of XLP patients with EBV invariably results in fatal mononucleosis, agammaglobulinemia or B-cell lymphoma. The XLP gene lies within a 10 cM region in Xq25 between DXS42 and DXS10. Initial chromosome studies revealed an interstitial, cytogenetically visible deletion in Xq25 in one XLP family (43-004). We estimated the size of the Xq25 deletion by dual laser flow karyotyping to involve 2% of the X chromosome, or approximately 3 Mbp of DNA sequences. To further delineate the deletion we performed a series of pulsed field gel electrophoresis (PFGE) analyses which showed that DXS6 and DXS100, two Xq25-specific markers, are missing from 45-004 DNA. Five yeast artificial chromosomes (YACs) from a chromosome X specific YAC library containing sequences deleted in patient`s 43-004 DNA were isolated. These five YACs did not overlap, and their end fragments were used to screen the CEPH MegaYAC library. Seven YACs were isolated from the CEPH MegaYAC library. They could be arranged into a contig which spans between DXS6 and DXS100. The contig contains a minimum of 2.5 Mbp of human DNA. A total of 12 YAC end clone, lambda subclones and STS probes have been used to order clones within the contig. These reagents were also used in Southern blot and patients showed interstitial deletions in Xq25. The size of these deletions range between 0.5 and 2.5 Mbp. The shortest deletion probably represents the critical region for the XLP gene.

First INTEGRAL observations of Cygnus X-3

DEFF Research Database (Denmark)

Vilhu, O.; Hjalmarsdotter, L.; Zdziarski, A.A.

2003-01-01

We present the first INTEGRAL results on Cyg X-3 from the PV phase observations of the Cygnus region. The source was clearly detected by the JEM-X, ISGRI and SPI. The INTEGRAL observations were supported by simultaneous pointed RXTE observations. Their lightcurves folded over the 4.8 hour binary ...... with parameters similar to those found for black-hole binaries at high Eddington rates....

X-ray fluorescent elemental analysis. Ch. 16

International Nuclear Information System (INIS)

Baryshev, V.; Kulipanov, G.; Skrinsky, A.

1991-01-01

X-ray fluorescence analysis (XFA) is used worldwide to define a quantitative content of the elements as well as to visualize the distribution of elements in different regions (element mapping). Utilization of synchrotron radiation (SR) to excite X-ray fluorescence enables the XFA method to be qualitatively improved. This chapter reviews the experimental work in especially the last decade (author). 71 refs.; 24 figs.; 3 tabs

Ab initio study of domain structures in half-metallic CoTi{sub 1−x}Mn{sub x}Sb and thermoelectric CoTi{sub 1−x}Sc{sub x}Sb half-Heusler alloys

Energy Technology Data Exchange (ETDEWEB)

Miranda Mena, Joaquin, E-mail: joaquin.miranda@uni-bayreuth.de; Schoberth, Heiko G.; Gruhn, Thomas; Emmerich, Heike

2015-11-25

We present first-principles calculations of the electronic density of state, the structures in CoTi{sub 1−x}Sc{sub x}Sb and CoTi{sub 1−x}Mn{sub x}Sb. In addition for the latter we calculate magnetic moments. Systems with different stoichiometries are compared and low energy configurations are determined using a cluster expansion procedure. For all studied manganese concentrations, x > 0, CoTi{sub 1−x}Mn{sub x}Sb is half-metallic and magnetic, which make it interesting for spintronic applications. In contrast, with increasing scandium concentration, the band gap of CoTi{sub x}Sc{sub 1-x}Sb closes continuously, while the material changes from a semiconductor to a non-magnetic metal. For low Sc doping this material is well suited for thermoelectric applications. The electronic states close to the Fermi energy are strongly influenced by the distribution of Ti and Mn (or Ti and Sc). This has important consequences for the usage of materials in application fields like spintronics and thermoelectrics. In general, a phase separation of the alloys into a Ti rich and a Ti poor phase is energetically favored. Using mean field theory we create a phase diagram that shows the coexistence and the spinodal region. A spontaneous demixing can be used for the creation of nanodomains within the material. In the case of CoTi{sub 1−x}Sc{sub x}Sb, the resulting reduced lattice thermal conductivity is beneficial for thermoelectric applications, while in CoTi{sub 1−x}Mn{sub x}Sb the nanodomains are detrimental for polarization.

Multilayer X-ray imaging systems

Science.gov (United States)

Shealy, D. L.; Hoover, R. B.; Gabardi, D. R.

1986-01-01

An assessment of the imaging properties of multilayer X-ray imaging systems with spherical surfaces has been made. A ray trace analysis was performed to investigate the effects of using spherical substrates (rather than the conventional paraboloidal/hyperboloidal contours) for doubly reflecting Cassegrain telescopes. These investigations were carried out for mirrors designed to operate at selected soft X-ray/XUV wavelengths that are of significance for studies of the solar corona/transition region from the Stanford/MSFC Rocket X-Ray Telescope. The effects of changes in separation of the primary and secondary elements were also investigated. These theoretical results are presented as well as the results of ray trace studies to establish the resolution and vignetting effects as a function of field angle and system parameters.

Growth of highly transparent Cd{sub x}Zn{sub 1−x}O (CZO) thin films: Structural and optical studies

Energy Technology Data Exchange (ETDEWEB)

Gautam, Naina, E-mail: nainagtm@gmail.com [Department of Electronic Science, University of Delhi South Campus, New Delhi 110023 (India); Singh, Fouran, E-mail: fouran@gmail.com [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gautam, Subodh K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Singh, R.G. [Department of Physics, Bhagini Nivedita College, Delhi University, Delhi 110043 (India); Ojha, S. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kapoor, A. [Department of Electronic Science, University of Delhi South Campus, New Delhi 110023 (India)

2015-11-25

The deposition of Cd{sub x}Zn{sub 1−x}O thin films with different cadmium concentrations i.e., x = 0.0, 0.05, 0.20 by sol–gel spin coating is reported. The doping fraction of Cd in ZnO films was measured by Rutherford backscattering spectrometry (RBS), while the surface morphology was studied by scanning electron microscopy (SEM). Grazing incidence X-ray diffraction (GIXRD) study was carried out for the structural investigations and reveals hexagonal wurtzite structure with polycrystalline nature. The various structural parameters are calculated including the lattice constants ‘a’ and ‘c’, stress (σ), strain (ε) and internal parameter (u). For x = 0.20 Cd content, the formation of secondary phase of the cubic CdO at 33.12° (111) and 38.41° (200) is observed and this is further confirmed by micro-Raman studies, where the TO mode emerges at ∼261.5 cm{sup −1}. The basic wurtzite structure is maintained as ‘c/a’ ratio and internal parameter ‘u’ found to be closer to the ideal values. All the films are found to be highly transparent in the visible region and a bending of the near band edge (NBE) absorption is observed with Cd doping. It is further confirmed by calculating the Urbach energy (E{sub u}), which is found to be increased from 0.14 eV (for x = 0.0) to 0.26 eV (for x = 0.20) with maximum value for the lightly doped films i.e. x = 0.05. However, the optical band gap is found to decrease from 3.26 eV (for x = 0.0) to 3.08 eV (for x = 0.20). - Highlights: • High transparent Cd{sub x}Zn{sub 1−x}O (CZO) thin films with an average transparency of ∼85% in the visible region. • Band-gap tuning is achieved by Cd doping in ZnO. • Segregation of cubic rock-salt CdO phase upon high doping as confirmed by Micro-Raman and SEM investigations.

X-Ray Emission from Compact Sources

Energy Technology Data Exchange (ETDEWEB)

Cominsky, L

2004-03-23

This paper presents a review of the physical parameters of neutron stars and black holes that have been derived from X-ray observations. I then explain how these physical parameters can be used to learn about the extreme conditions occurring in regions of strong gravity, and present some recent evidence for relativistic effects seen in these systems. A glossary of commonly used terms and a short tutorial on the names of X-ray sources are also included.

Analyais of solar X-ray emission line profiles

International Nuclear Information System (INIS)

Burek, A.J.; Marrus, D.M.; Blake, R.L.; Fenimore, E.E.

1981-01-01

We report results of the analysis of the X-ray emission line profiles for the Ne X La and Fe XVII 4d 1 P 1 lines produced in an active region that was undergoing a radio and X-ray gradual rise and fall (GRF) in intensity. The spectra were obtained with collimated Bragg spectrometers launched on a rocket from White Sands Missile Range on 1976 March 26. Using a crystal of ammonium acid phthalate, we have fully resolved the Ne X La and Fe XVII 4d 1 P 1 lines, permitting an accurate determinination of the Ne X La intensity and allowing Doppler broadened profiles for lines formed from ions having greatly different atomic mass and charge to be measured. An isothermal model derived from the Ne IX/Ne X resonance line intensity ratio gives an electron temperature of 3.4 x 10 6 K. An isothermal model, however, fails to account for the intensities of all lines and continuum observed. All multitemperature models that do reproduce the observed relative line intensities require the presence of a hot plasma component with an electron temperature in excess of 5 x 10 6 K. The presence of a high temperature component is also suggested by the measured line to continuum ratio of 3.6 in the 12--15 A wavelength interval. Interpretation of the line profiles in terms of a multitemperature model requires an rms turbulence velocity of 48 +- 15 km s -1 for Fe XVII 1 P 1 and 74 +- 54 km s - 2exclamation for Ne X La at the 95% confidence level. Collimated scans across the active region show the presence of a compact source of intense X-ray emission close to the magnetic neutral line, which is very probably the GRF plasma

Recent developments in low x physics

International Nuclear Information System (INIS)

Kwiecinski, J.

1997-02-01

The QCD expectations for the behaviour of the deep inelastic scattering structure functions in the region of small values of the Bjoerken parameter x are summarized. The Balitzkij, Lipatov, Fadin, Kuraev (BFKL) equation which sums the leading powers of αln(1/x) is described and confronted with the ''conventional'' formalism based on the leading order QCD evolution equations. The small x behaviour of the spin dependent structure function g 1 is also discussed. The dedicated measurements of the hadronic final state in deep inelastic scattering at small x probing the QCD pomeron are described. This includes discussion of the deep inelastic scattering accompanied by forward jets as well as production of forward prompt photons and π 0 -s. Finally the basic facts concerning the deep inelastic diffraction are briefly summarized. (author)

Defect chalcopyrite Cu(In{sub 1-x}Ga{sub x}){sub 3}Se{sub 5} (0<x<1) materials and high-Ga-content Cu(In,Ga) Se{sub 2}-based solar cells

Energy Technology Data Exchange (ETDEWEB)

Contreras, M.A.; Wiesner, H.; Niles, D.; Ramanathan, K.; Matson, R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

1996-05-01

Crystallographic, optical, and electrical properties of defect chalcopyrite Cu(In{sub 1{minus}x}Ga{sub x}){sub 3}Se{sub 5} (0<x<1) materials in polycrystalline thin-film form are reported. Also, an energy band alignment between such materials and CdS has been calculated from X-ray photoelectron spectroscopy data. A comparison of some properties against published data on similarly prepared chalcopyrite CuIn{sub 1 {minus}x}Ga{sub x}Se{sub 2} absorber materials is presented. Considering the chalcopyrite/defect chalcopyrite junction model, the authors postulate that the traditionally poor device performance of uniform high-Ga-content absorbers (x>0.3) is due to a relatively inferior character - both structural and electrical - at the very chalcopyrite/defect chalcopyrite interface. They demonstrate that this situation can be circumvented (for absorbers with x>0.3) by properly engineering such an interface by reducing Ga content in the region near the surface of the absorber.

A theoretical and experimental evaluation of the microangiographic fluoroscope: A high-resolution region-of-interest x-ray imager

International Nuclear Information System (INIS)

Jain, Amit; Bednarek, D. R.; Ionita, Ciprian; Rudin, S.

2011-01-01

Purpose: The increasing need for better image quality and high spatial resolution for successful endovascular image-guided interventions (EIGIs) and the inherent limitations of the state-of-the-art detectors provide motivation to develop a detector system tailored to the specific, demanding requirements of neurointerventional applications.Method: A microangiographic fluoroscope (MAF) was developed to serve as a high-resolution, region-of-interest (ROI) x-ray imaging detector in conjunction with large lower-resolution full field-of-view (FOV) state-of-the-art x-ray detectors. The newly developed MAF is an indirect x-ray imaging detector capable of providing real-time images (30 frames per second) with high-resolution, high sensitivity, no lag and low instrumentation noise. It consists of a CCD camera coupled to a Gen 2 dual-stage microchannel plate light image intensifier (LII) through a fiber-optic taper. A 300 μm thick CsI(Tl) phosphor serving as the front end is coupled to the LII. The LII is the key component of the MAF and the large variable gain provided by it enables the MAF to operate as a quantum-noise-limited detector for both fluoroscopy and angiography. Results: The linear cascade model was used to predict the theoretical performance of the MAF, and the theoretical prediction showed close agreement with experimental findings. Linear system metrics such as MTF and DQE were used to gauge the detector performance up to 10 cycles/mm. The measured zero frequency DQE(0) was 0.55 for an RQA5 spectrum. A total of 21 stages were identified for the whole imaging chain and each stage was characterized individually. Conclusions: The linear cascade model analysis provides insight into the imaging chain and may be useful for further development of the MAF detector. The preclinical testing of the prototype detector in animal procedures is showing encouraging results and points to the potential for significant impact on EIGIs when used in conjunction with a state

A DEEP CHANDRA ACIS STUDY OF NGC 4151. I. THE X-RAY MORPHOLOGY OF THE 3 kpc DIAMETER CIRCUM-NUCLEAR REGION AND RELATION TO THE COLD INTERSTELLAR MEDIUM

International Nuclear Information System (INIS)

Wang Junfeng; Fabbiano, Giuseppina; Risaliti, Guido; Elvis, Martin; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.; Dumas, Gaelle; Schinnerer, Eva

2011-01-01

We report on the imaging analysis of ∼200 ks sub-arcsecond resolution Chandra Advanced CCD Imaging Spectrometer (ACIS-S) observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the southwest from the nucleus, much farther than seen in earlier X-ray studies. The terminus of the northeastern X-ray emission is spatially coincident with a CO gas lane, where the outflow likely encounters dense gas in the host galactic disk. X-ray emission is also detected outside the boundaries of the ionization cone, which indicates that the gas there is not completely shielded from the nuclear continuum, as would be the case for a molecular torus collimating the bicone. In the central r 2 emission and dusty spirals we find in an Hubble Space Telescope V - H color image. The agreement between the observed H 2 line flux and the value predicted from X-ray-irradiated molecular cloud models supports photo-excitation by X-rays from the active nucleus as the origin of the H 2 line, although contribution from UV fluorescence or collisional excitation cannot be ruled out with current data. The discrepancy between the mass of cold molecular gas inferred from recent CO and near-infrared H 2 observations may be explained by the anomalous CO abundance in this X-ray-dominated region. The total H 2 mass derived from the X-ray observation agrees with the recent measurement by Storchi-Bergmann et al.

Neutronic evaluation of annular fuel rods to assemblies 13 x 13, 14 x 14 and 15 x 15

International Nuclear Information System (INIS)

Silva, Raphael H.M.; Ramos, Mario C.; Velasquez, Carlos E.; Silva, Clarysson A.M. da; Pereira, Cláubia; Costa, Antonella L.

2017-01-01

Research and development in nuclear reactor field has been proposed a new concept of fuel rod such as annular shape. The design of the annular fuel rods allows the coolant flow through the inner and outer side of it. Such project was proposed as an alternative to the traditional fuel rods used in LWR reactors. This new geometry allows an increase in power density in the reactor core with greater heat transfer from the fuel to the coolant which reduces the temperature in central region of the rod, in which a better configuration and dimension of fuel elements are aimed due to improvement of cooling in possible replacement of PWR traditional rods for annular rods. The aim of this work is to evaluate the neutronic parameters of fuel element with annular fuel rods where three configurations were studied: 13 x 13, 14 x 14 and 15 x 15. The goal is compare the neutronic between the advanced and the standard fuel assembly 16 x 16. In these studies, the external dimension and the moderator to fuel volume ratio (V M /V F ) of standard 16 x 16 is the same in all annular fuels assemblies. The MCNPX 2.6.0 (Monte Carlo N-Particle eXtended – version 2.6.0) code was used in all simulations. After all procedures, the annular fuel assemblies 13 have obtained greater neutronics parameters and were selected to more neutronics simulations. (author)

Neutronic evaluation of annular fuel rods to assemblies 13 x 13, 14 x 14 and 15 x 15

Energy Technology Data Exchange (ETDEWEB)

Silva, Raphael H.M.; Ramos, Mario C.; Velasquez, Carlos E.; Silva, Clarysson A.M. da; Pereira, Cláubia; Costa, Antonella L., E-mail: rapha.galo@hotmail.com, E-mail: marc5663@gmail.com, E-mail: carlosvelcab@hotmail.com, E-mail: clarysson@nuclear.ufmg.br, E-mail: claubia@nuclear.ufmg.br, E-mail: antonella@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

2017-07-01

Research and development in nuclear reactor field has been proposed a new concept of fuel rod such as annular shape. The design of the annular fuel rods allows the coolant flow through the inner and outer side of it. Such project was proposed as an alternative to the traditional fuel rods used in LWR reactors. This new geometry allows an increase in power density in the reactor core with greater heat transfer from the fuel to the coolant which reduces the temperature in central region of the rod, in which a better configuration and dimension of fuel elements are aimed due to improvement of cooling in possible replacement of PWR traditional rods for annular rods. The aim of this work is to evaluate the neutronic parameters of fuel element with annular fuel rods where three configurations were studied: 13 x 13, 14 x 14 and 15 x 15. The goal is compare the neutronic between the advanced and the standard fuel assembly 16 x 16. In these studies, the external dimension and the moderator to fuel volume ratio (V{sub M}/V{sub F}) of standard 16 x 16 is the same in all annular fuels assemblies. The MCNPX 2.6.0 (Monte Carlo N-Particle eXtended – version 2.6.0) code was used in all simulations. After all procedures, the annular fuel assemblies 13 have obtained greater neutronics parameters and were selected to more neutronics simulations. (author)

Crystal structure and electrical resistivity studies of Gd(Fe1-x Cox)2 intermetallics

International Nuclear Information System (INIS)

Onak, M.; Guzdek, P.; Stoch, P.; Chmist, J.; Bednarski, M.; Panta, A.; Pszczola, J.

2007-01-01

From X-ray analysis (295 K) it was found that the cubic, MgCu 2 -type, Fd3m crystal structure appears across the Gd(Fe 1-x Co x ) 2 series. Electrical resistivity measurements for the Gd(Fe 1-x Co x ) 2 intermetallics were performed in a wide temperature region and the parameters characterizing the resistivity dependence on temperature and composition were determined. The differential of the electrical resistivity against temperature was used to estimate Curie temperatures. The Curie temperature versus x, high and moderately increasing in the iron-rich area, rapidly drops in the cobalt-rich region. The obtained results are compared with the data known for the Dy(Fe 1-x Co x ) 2 series. The Curie temperature is related to both the number of 3d electrons and the de Gennes factor

Disentangling the gamma-ray emission towards Cygnus X: Sh2-104

Science.gov (United States)

Gotthelf, Eric

2015-09-01

We have just discovered distinct X-ray emission coincident with VER J2018+363, a TeV source recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. NuSTAR reveals a hard point source and a diffuse nebula adjacent to and possibly part of Sh2-104, a compact HII region containing several young massive stellar clusters. There is reasonable evidence that these X-rays probe the origin of the gamma-ray flux, however, unrelated extragalactic sources need to be excluded. We propose a short Chandra observation to localize the X-ray emission to identify a putative pulsar or stellar counterpart(s). This is an important step to fully understand the energetics of the MGRO J2019+37 complex and the production of gamma-rays in star formation regions, in general.

Edge enhancement algorithm for low-dose X-ray fluoroscopic imaging.

Science.gov (United States)

Lee, Min Seok; Park, Chul Hee; Kang, Moon Gi

2017-12-01

Low-dose X-ray fluoroscopy has continually evolved to reduce radiation risk to patients during clinical diagnosis and surgery. However, the reduction in dose exposure causes quality degradation of the acquired images. In general, an X-ray device has a time-average pre-processor to remove the generated quantum noise. However, this pre-processor causes blurring and artifacts within the moving edge regions, and noise remains in the image. During high-pass filtering (HPF) to enhance edge detail, this noise in the image is amplified. In this study, a 2D edge enhancement algorithm comprising region adaptive HPF with the transient improvement (TI) method, as well as artifacts and noise reduction (ANR), was developed for degraded X-ray fluoroscopic images. The proposed method was applied in a static scene pre-processed by a low-dose X-ray fluoroscopy device. First, the sharpness of the X-ray image was improved using region adaptive HPF with the TI method, which facilitates sharpening of edge details without overshoot problems. Then, an ANR filter that uses an edge directional kernel was developed to remove the artifacts and noise that can occur during sharpening, while preserving edge details. The quantitative and qualitative results obtained by applying the developed method to low-dose X-ray fluoroscopic images and visually and numerically comparing the final images with images improved using conventional edge enhancement techniques indicate that the proposed method outperforms existing edge enhancement methods in terms of objective criteria and subjective visual perception of the actual X-ray fluoroscopic image. The developed edge enhancement algorithm performed well when applied to actual low-dose X-ray fluoroscopic images, not only by improving the sharpness, but also by removing artifacts and noise, including overshoot. Copyright © 2017 Elsevier B.V. All rights reserved.

UV and X-ray Evolution of AR12230 as Observed with IRIS and FOXSI-II

Science.gov (United States)

Ryan, Daniel; Christe, Steven; Glesener, Lindsay; Vievering, Julie; Krucker, Sam; Ishikawa, Shin-Nosuke

2017-08-01

We present a multi-spectral and spatio-temporal analysis of AR12230 using both UV and X-ray spectroscopic imaging obtained as part of a coordinated observing campaign on 11 December 2014. The campaign involved IRIS (Interface Region Imaging Spectrometer) -- which provides both UV imaging and slit spectrograph observations of optically thick chromospheric and transition region emission -- and FOXSI-II (Focusing Optics X-ray Solar Imager) -- the second in a series of sounding rocket flights which combines grazing incidence direct focusing optics to produce solar X-ray spectroscopic imaging in the range 4-15keV. The active region exhibits a prolonged compact brightening in the IRIS 1330 A and 1400 A slit-jaw channels near the center of the active region throughout the duration of the observations. In the early phase of the observations FOXSI-II shows an X-ray source approximately 20x20 arcsec centered at the same location. The X-ray spectra show the presence of hot (~8 MK) thermal plasma and is suggestive of the presence of non-thermal electrons.. Later, two additional transient, spatially extended, simultaneous brightenings are observed, one of which was captured by the IRIS slit spectrograph. We combine these observations to explore the evolution and topology of the active region. Hydrodynamic modeling of the chromosphere is used to place a limit on the amount of non-thermal electrons required to produce the observed UV emission. This result is then compared to the limit inferred from the FOXSI-II X-ray spectra. Thus, we explore the role of non-thermal electrons and hydrodynamics in the energization and evolution of plasma in active regions.

Meiotic Consequences of Genetic Divergence Across the Murine Pseudoautosomal Region

OpenAIRE

Dumont, Beth L.

2017-01-01

The production of haploid gametes during meiosis is dependent on the homology-driven processes of pairing, synapsis, and recombination. On the mammalian heterogametic sex chromosomes, these key meiotic activities are confined to the pseudoautosomal region (PAR), a short region of near-perfect sequence homology between the X and Y chromosomes. Despite its established importance for meiosis, the PAR is rapidly evolving, raising the question of how proper X/Y segregation is buffered against the ...

Age- and region-specific imbalances of basal amino acids and monoamine metabolism in limbic regions of female Fmr1 knock-out mice.

Science.gov (United States)

Gruss, Michael; Braun, Katharina

2004-07-01

The Fragile X syndrome, a common form of mental retardation in humans, originates from the loss of expression of the Fragile X mental retardation gene leading to the absence of the encoded Fragile X mental retardation protein 1 (FMRP). A broad pattern of morphological and behavioral abnormalities is well described for affected humans as well as Fmr1 knock-out mice, a transgenic animal model for the human Fragile X syndrome. In the present study, we examined neurochemical differences between female Fmr1 knock-out and wildtype mice with particular focus on neurotransmission. Significant age- and region-specific differences of basal tissue neurotransmitter and metabolite levels measured by high performance liquid chromatography were found. Those differences were more numerous in juvenile animals (postnatal day (PND) 28-31) compared to adults (postnatal day 209-221). In juvenile female knock-out mice, especially aspartate and taurine were increased in cortical regions, striatum, cerebellum, and brainstem. Furthermore, compared to the wildtype animals, the juvenile knock-out mice displayed an increased level of neuronal inhibition in the hippocampus and brainstem reflected by decreased ratios of (aspartate + glutamate)/(taurine + GABA), as well as an increased dopamine (DA) turnover in cortical regions, striatum, and hippocampus. These results provide the first evidence that the lack of FMRP expression in female Fmr1 knock-out mice is accompanied by age-dependent, region-specific alterations in brain amino acids, and monoamine turnover, which might be related to the reported synaptical and behavioural alterations in these animals.

x- and xi-scaling of the Nuclear Structure Function at Large x

International Nuclear Information System (INIS)

Arrington, J.; Armstrong, C. S.; Averett, T.; Baker, O. K.; Bever, L. de; Bochna, C. W.; Boeglin, W.; Bray, B.; Carlini, R. D.; Collins, G.; Cothran, C.; Crabb, D.; Day, D.; Dunne, J. A.; Dutta, D.; Ent, R.; Filippone, B. W.; Honegger, A.; Hughes, E. W.; Jensen, J.; Jourdan, J.; Keppel, C. E.; Koltenuk, D. M.; Lindgren, R.; Lung, A.; Mack, D. J.; McCarthy, J.; McKeown, R. D.; Meekins, D.; Mitchell, J. H.; Mkrtchyan, H. G.; Niculescu, G.; Niculescu, I.; Petitjean, T.; Rondon, O.; Sick, I.; Smith, C.; Terburg, B.; Vulcan, W. F.; Wood, S. A.; Yan, C.; Zhao, J.; Zihlmann, B.

2001-01-01

Inclusive electron scattering data are presented for 2 H and Fe targets at an incident electron energy of 4.045 GeV for a range of momentum transfers from Q 2 = 1 to 7 (GeV/c) 2 . Data were taken at Jefferson Laboratory for low values of energy loss, corresponding to values of Bjorken x greater than or near 1. The structure functions do not show scaling in x in this range, where inelastic scattering is not expected to dominate the cross section. The data do show scaling, however, in the Nachtmann variable ξ. This scaling may be the result of Bloom Gilman duality in the nucleon structure function combined with the Fermi motion of the nucleons in the nucleus. The resulting extension of scaling to larger values of ξ opens up the possibility of accessing nuclear structure functions in the high-x region at lower values of Q 2 than previously believed

The X-ray microscopy project at saga SLS

International Nuclear Information System (INIS)

Yasumoto, M.; Ishiguro, E.; Takemoto, K.; Kihara, H.; Kamijo, N.; Tomimasu, T.; Tsurushima, T.; Takahara, A.; Hara, K.; Chikaura, Y.

2002-01-01

A new high resolution X-ray microscopy project has been proposed at Saga synchrotron light source, which is a third generation synchrotron light facility in Japan. Two microscopy beamlines are planned for this project. One is a scanning microscope in the water window region, and the other is a full-field imaging microscope in the multi-keV X-ray energy region. To demonstrate the feasibility of the project, the optical layout of the scanning microscope was designed. The beamline mainly consists of a 3.5 cm periodical undulator, a varied line-spacing plane grating monochromator (600 lines/mm) and an end-station including a zone plate. Thus, the calculated X-ray properties focused on the sample position are as follows: the spot size is ∼ 70 nm, the monochromaticity is ∼2000, and the photon flux is 10 9 ∼ 10 10 photons/sec. (authors)

ICF ignition capsule neutron, gamma ray, and high energy x-ray images

Science.gov (United States)

Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

2003-03-01

Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

Regional emission balances for Belgium in the year 1990

International Nuclear Information System (INIS)

Bouma, J.W.J.

1993-01-01

Regional emission balances are vital with regard to an efficient energy and environmental policy. The emission balances were calculated on the basis of a top-down approach, making use of the regional energy balances for the three regions in Belgium (Wallonie, Brussels, Flanders regions). The emissions of NO X -, SO 2 -and CO 2 -gases in 1990 for the Flanders, the Wallonie and the Brussels region are presented. (A.S.)

Hard X-ray photoemission spectroscopy

International Nuclear Information System (INIS)

Kobayashi, Keisuke

2009-01-01

Except in the very early stage of the development of X-ray photoemission spectroscopy (XPS) by Kai Siegbahn and his coworkers, the excitation sources for XPS studies have predominantly been the Al Kα and Mg Kα emission lines. The advent of synchrotron radiation sources opened up the possibility of tuning the excitation photon energy with much higher throughputs for photoemission spectroscopy, however the excitation energy range was limited to the vacuum ultra violet and soft X-ray regions. Over the past 5-6 years, bulk-sensitive hard X-ray photoemission spectroscopy using high-brilliance high-flux X-rays from third generation synchrotron radiation facilities has been developed. This article reviews the history of HXPES covering the period from Kai Siegbahn and his coworkers' pioneering works to the present, and describes the fundamental aspects, instrumentation, applications to solid state physics, applied physics, materials science, and industrial applications of HXPES. Finally, several challenging new developments which have been conducted at SPring-8 by collaborations among several groups are introduced.

Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

Science.gov (United States)

Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

2016-01-01

For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

Control of CydB and GltA1 expression by the SenX3 RegX3 two component regulatory system of Mycobacterium tuberculosis.

Directory of Open Access Journals (Sweden)

Gretta Roberts

Full Text Available Two component regulatory systems are used widely by bacteria to coordinate changes in global gene expression profiles in response to environmental signals. The SenX3-RegX3 two component system of Mycobacterium tuberculosis has previously been shown to play a role in virulence and phosphate-responsive control of gene expression. We demonstrate that expression of SenX3-RegX3 is controlled in response to growth conditions, although the absolute changes are small. Global gene expression profiling of a RegX3 deletion strain and wild-type strain in different culture conditions (static, microaerobic, anaerobic, as well as in an over-expressing strain identified a number of genes with changed expression patterns. Among those were genes previously identified as differentially regulated in aerobic culture, including ald (encoding alanine dehydrogenase cyd,encoding a subunit of the cytochrome D ubiquinol oxidase, and gltA1, encoding a citrate synthase. Promoter activity in the upstream regions of both cydB and gltA1 was altered in the RegX3 deletion strain. DNA-binding assays confirmed that RegX3 binds to the promoter regions of ald, cydB and gltA1 in a phosphorylation-dependent manner. Taken together these data suggest a direct role for the SenX-RegX3 system in modulating expression of aerobic respiration, in addition to its role during phosphate limitation.

A new resource for characterizing X-linked genes in Drosophila melanogaster: systematic coverage and subdivision of the X chromosome with nested, Y-linked duplications.

Science.gov (United States)

Cook, R Kimberley; Deal, Megan E; Deal, Jennifer A; Garton, Russell D; Brown, C Adam; Ward, Megan E; Andrade, Rachel S; Spana, Eric P; Kaufman, Thomas C; Cook, Kevin R

2010-12-01

Interchromosomal duplications are especially important for the study of X-linked genes. Males inheriting a mutation in a vital X-linked gene cannot survive unless there is a wild-type copy of the gene duplicated elsewhere in the genome. Rescuing the lethality of an X-linked mutation with a duplication allows the mutation to be used experimentally in complementation tests and other genetic crosses and it maps the mutated gene to a defined chromosomal region. Duplications can also be used to screen for dosage-dependent enhancers and suppressors of mutant phenotypes as a way to identify genes involved in the same biological process. We describe an ongoing project in Drosophila melanogaster to generate comprehensive coverage and extensive breakpoint subdivision of the X chromosome with megabase-scale X segments borne on Y chromosomes. The in vivo method involves the creation of X inversions on attached-XY chromosomes by FLP-FRT site-specific recombination technology followed by irradiation to induce large internal X deletions. The resulting chromosomes consist of the X tip, a medial X segment placed near the tip by an inversion, and a full Y. A nested set of medial duplicated segments is derived from each inversion precursor. We have constructed a set of inversions on attached-XY chromosomes that enable us to isolate nested duplicated segments from all X regions. To date, our screens have provided a minimum of 78% X coverage with duplication breakpoints spaced a median of nine genes apart. These duplication chromosomes will be valuable resources for rescuing and mapping X-linked mutations and identifying dosage-dependent modifiers of mutant phenotypes.

Fundamental studies for CT in the oral region

International Nuclear Information System (INIS)

Suzuki, Shinichiro

1984-01-01

Fundamental studies were attempted regarding the clinical application of CT (TCT-60A) in the oral region. The investigation assessed the following: 1) calculation of CT-No for oral hard tissues, 2) test for linearity CT-No vs. the linear attenuation coefficient in high X-ray attenuation materials, 3) observation of artifacts caused by dental materials and 4) measurement of patient doses of CT used at the maxillary sinus. The results obtained were as follows. 1) Calculated CT-No (E=70 KeV) values for oral hard tissues were enamel 3.51 x 10 3 , dentine 2.40 x 10 3 , cementum 1.88 x 10 3 , cortical bone 1.48 x 10 3 and mandible 1.01 x 10 3 . 2) Linearity for CT-No vs. the linear attenuation coefficient gave a good relative coefficient between lucite and teflon, but linearity between lucite and aluminum was not good enough. 3) Three different artifacts from the copper rod were observed: (1) connection line artifact, (2) star-burst artifact and (3) figure-eight artifact. 4) Under shot caused by composite resin was observed, and artifact from both the radiopaque composite resin and amalgam were the same kinds as those from the copper rod. 5) Calculated CT-No (E=66 KeV) values for dental materials were copper 5.48 x 10 4 , composite resin 1.24 x 10 3 , radiopaque composite resin 4.65 x 10 3 and amalgam 2.27 x 10 5 . 6) Absorbed doses of lenses and thyroid gland using CT at the mixillary sinus region were 59 mrad (59 x 10 -2 mGy) and 17 mrad (17 x 10 -2 mGy) for a single scanning. 7) The volume dose of the head under a single CT scanning was estimated as 820 g.rad (820 x 10 -5 Kg.Gy) by the TLD method, and 900 g.rad (900 x 10 -5 Kg.Gy) by the film dosimetry method. The difference in these values was considered to be the effect arising from ununiformity of the X-ray beam. (author)

Irradiated ISM : Discriminating between cosmic rays and X-rays

NARCIS (Netherlands)

Meijerink, R.; Spaans, M.; Israel, F. P.

2006-01-01

The interstellar medium ( ISM) at the centers of active galaxies is exposed to a combination of cosmic-ray, far-ultraviolet (FUV), and X-ray radiation. We apply photodissociation region (PDR) models to this ISM with both "normal" and highly elevated (5 x 10(-15) s(-1)) cosmic- ray (CR) rates and

Microstructural and optical properties of spinel oxide M{sub x}Co{sub 2−x}MnO{sub 4} (M = Ni, Zn or Cu; 0 < x < 1) thin films prepared by inorganic polycondensation and dip-coating methods

Energy Technology Data Exchange (ETDEWEB)

Le, Thi Ly; Guillemet-Fritsch, Sophie; Dufour, Pascal; Tenailleau, Christophe, E-mail: tenailleau@chimie.ups-tlse.fr

2016-08-01

Spinel oxide nanoparticles of M{sub x}Co{sub 2−x}MnO{sub 4} (M = Ni, Zn, Cu; 0 < x < 1) were prepared at 120 °C by the inorganic polycondensation method. Phase composition and microstructure of each sample powder thus obtained were characterized by X-ray diffraction, X-ray fluorescence and scanning electron microscopy. Nanoparticles are well crystallized and uniformly distributed in both shape and size. Colloidal dispersions were stabilized in a low cost and environmentally friendly solvent solution. Spinel oxide thin films were then deposited on glass substrates by using the dip-coating technique. Their optical properties were measured in the 300–1100 nm wavelength range. Thin films show extremely good absorbance in the ultra-violet and blue regions. The highest absorbance observed in the red region was for x = 0.15 in zinc. A smaller direct band gap was determined when a low amount of doping M element was introduced in the cobalt and manganese spinel oxide material. - Highlights: • Pure complex spinel oxide nanoparticles synthesis at low T • Low cost method used to stabilize colloidal dispersions • Preparation of homogenous light absorber thin films by dip-coating • Adjustable optical properties and band gaps with the dopants.

Investigations of time resolved x-ray wide-angle scattering and x-ray small-angle scattering at DESY

International Nuclear Information System (INIS)

Zachmann, H.G.; Gehrke, R.; Prieske, W.; Riekel, C.

1985-01-01

Instrumentation is described for the simultaneous wide-angle and small-angle x-ray scattering. The method was applied to the study of the isothermal crystallization of polyethylene terephthalates. In agreement with the classical theories of crystallization, the data showed that the density difference between the crystals and the non-crystalline regions does not change with time. The mechanisms of melting, recrystallization, and crystal thickening were investigated by small-angle x-ray scattering with stepwise changes and continuous changes of temperature using polyethylene terephthalate

Where should MMS look for the electron and ion diffusion regions?

Science.gov (United States)

Lapenta, G.; Goldman, M. V.; Newman, D. L.; Olshevsky, V.

2015-12-01

Our message is that if we think of reconnection with the usual cartoon, the MMS mission should follow the advice of Indiana Jones: X never marks the spot. Based on 3D fully kinetic simulations started with a well defined x-line, we observe that reconnection transitions towards a more chaotic regime. Two fronts develop downstream of the x-line where the outflow meets the pre-existing plasma. In the fronts an instability develops caused by the local gradients of the density. The consequence is the break up of the fronts in a fashion similar to the classical fluid Rayleigh-Taylor instability with the formation of "fingers" of plasma and embedded magnetic fields. These fingers interact and produce secondary reconnection sites. We present several different diagnostics that prove the existence of these secondary reconnection sites. Each site is surrounded by its own electron diffusion region.At the fronts the ions are generally not magnetized and considerable ion slippage is present. The discovery we present is that electrons are also slipping, forming localized diffusion regions near secondary reconnection sites [1].The consequence of this discovery is twofold. First, the instability in the fronts has strong energetic implications. We observe that the energy transfer locally is very strong, an order of magnitude stronger than in the "X" line. However, this energy transfer is of both signs as it is natural for a wavy rippling with regions of magnetic to kinetic and regions of kinetic to magnetic energy conversion.Second, and most important for this session, is that MMS should not limit the search for electron diffusion regions to the location marked with X in all reconnection cartoons. Our simulations predict more numerous and perhaps more easily measurable electron diffusion regions in the fronts. [1] Lapenta, G et al., Nature Physics 11, 690-695 (2015)

X-ray spectra of PG quasars. I. The continuum from X-rays to infrared

International Nuclear Information System (INIS)

Elvis, M.; Green, R.F.; Bechtold, J.; Schmidt, M.; Neugebauer, G.; Kitt Peak National Observatory, Tucson, AZ; Steward Observatory, Tucson, AZ; Palomar Observatory, Pasadena, CA)

1986-01-01

Einstein IPC X-ray spectra for a sample of eight optically selected quasars from the Palomar Bright Quasar survey are presented. The quasars have a mean power law energy slope which in five individual cases is inconsistent with the value found in hard X-ray selection criterion rather than luminosity, redshift, or U-B color. New IUE and optical continuum spectra and infrared photometry are presented for these quasars. The data are combined into log vf(v) and log v distributions which support the decomposition of the overall quasar spectrum into a power law plus a superposed optical-UV big bump which may be due to an accretion disk. At least six of the quasars have vf(v)s which are roughly constant between their infrared and X-ray power laws, suggesting a strong link between the two regions. 104 references

The O(α3s) Heavy Flavor Contributions to the Charged Current Structure Function xF3(x,Q2) at Large Momentum Transfer

International Nuclear Information System (INIS)

Behring, A.; Bluemlein, J.; Freitas, A. de; Johannes Kepler Univ., Linz; Hasselhuhn, A.; Manteuffel, A. von; Schneider, C.

2015-08-01

We calculate the massive Wilson coefficients for the heavy flavor contributions to the non-singlet charged current deep-inelastic scattering structure function xF W+ 3 (x,Q 2 )+xF W- 3 (x,Q 2 ) in the asymptotic region Q 2 >>m 2 to 3-loop order in Quantum Chromodynamics (QCD) at general values of the Mellin variable N and the momentum fraction x. Besides the heavy quark pair production also the single heavy flavor excitation s→c contributes. Numerical results are presented for the charm quark contributions and consequences on the Gross-Llewellyn Smith sum rule are discussed.

X-ray scattering by interstellar dust

International Nuclear Information System (INIS)

Rolf, D.

1980-10-01

This thesis reports work carried out to make a first observation of x-rays scattered by interstellar dust grains. Data about the dust, obtained at wavelengths ranging from the infrared to ultra-violet spectral regions, are discussed in order to establish a useful description of the grains themselves. This is then used to estimate the magnitude and form of the expected x-ray scattering effect which is shown to manifest itself as a diffuse halo accompanying the image of a celestial x-ray source. Two x-ray imaging experiments are then discussed. The first, specifically proposed to look for this effect surrounding a point x-ray source, was the Skylark 1611 project, and comprised an imaging proportional counter coupled to an x-ray mirror. This is described up to its final calibration when the basis for a concise model of its point response function was established. The experiment was not carried out but its objective and the experience gained during its testing were transferred to the second of the x-ray imaging experiments, the Einstein Observatory. The new instrumental characteristics are described and a model for its point response function is developed. Using this, image data for the point x-ray source GX339-4 is shown to exhibit the sought after scattering phenomenon. (author)

High-density arrays of x-ray microcalorimeters for Constellation-X

Science.gov (United States)

Kilbourne, Caroline A.; Bandler, Simon R.; Brown, Ari D.; Chervenak, James A.; Figueroa-Feliciano, Enectali; Finkbeiner, Fred M.; Iyomoto, Naoko; Kelley, Richard L.; Porter, F. Scott; Saab, Tarek; Sadleir, John; White, Jennifer

2006-06-01

We have been developing x-ray microcalorimeters for the Constellation-X mission. Devices based on superconducting transition-edge sensors (TES) have demonstrated the potential to meet the Constellation-X requirements for spectral resolution, speed, and array scale (> 1000 pixels) in a close-packed geometry. In our part of the GSFC/NIST collaboration on this technology development, we have been concentrating on the fabrication of arrays of pixels suitable for the Constellation-X reference configuration. We have fabricated 8x8 arrays with 0.25-mm pixels arranged with 92% fill factor. The pixels are based on Mo/Au TES and Bi/Cu or Au/Bi absorbers. We have achieved a resolution of 4.0 eV FWHM at 6 keV in such devices, which meets the Constellation-X resolution requirement at 6 keV. Studies of the thermal transport in our Bi/Cu absorbers have shown that, while there is room for improvement, for 0.25-mm pixels the standard absorber design is adequate to avoid unacceptable line-broadening from position dependence caused by thermal diffusion. In order to improve reproducibility and to push closer to the 2-eV goal at 6 keV, however, we are refining the design of the TES and the interface to the absorber. Recent efforts to introduce a barrier layer between the Bi and the Mo/Au to avoid variable interface chemistry and thus improve the reproducibility of device characteristics have thus far yielded unsatisfactory results. However, we have developed a new set of absorber designs with contacts to the TES engineered to allow contact only in regions that do not serve as the active thermometer. We have further constrained the design so that a low-resistance absorber will not electrically short the TES. It is with such a design that we have achieved 4.0 eV resolution at 6 keV.

Structure and electronic properties of AlCrO{sub x}N{sub 1−x} thin films deposited by reactive magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Najafi, H.; Karimi, A. [Institute of Condensed Matter Physics (ICMP), Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Oveisi, E. [Electron Spectrometry and Microscopy Laboratory (LSME-ICMP), Swiss Federal Institute of Technology in Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Morstein, M. [PLATIT AG, Advanced Coating Systems, CH-2545 Selzach (Switzerland)

2014-12-01

In this study, the main attempt is devoted to investigating the microstructure and electronic properties of AlCrO{sub x}N{sub 1−x} films in a wide range of oxygen concentrations from 0 to 1. These oxynitride films were deposited by pulsed DC magnetron sputtering from Al{sub 55}Cr{sub 45} targets. Our results showed that films with x = O/(O + N) < 0.6, exhibit a cubic (B1) lattice with a well-developed columnar structure. The incorporation of oxygen into the films without any oxide segregation results in the formation of a substitutional AlCrO{sub x}N{sub 1−x} solid solution and material system behaves like nitrides electronically. In the range of oxygen contents from 0.6 ≤ O/(O + N) < 0.97, coatings with fine columns, diffuse boundaries and high values of metal vacancies were formed. However, the B1 lattice survived despite the large proportion of oxygen. According to the structural and electronic properties of the corresponding layers, we assign this region to the formation of an amorphous phase and metastable monoxides with a B1 structure. Coatings with O/(O + N) ≥ 0.97 are electronically assigned to a solid solution of α-(Al,Cr){sub 2}(O{sub 0.97},N{sub 0.03}){sub 3} with corundum lattice and finer columnar structure. - Highlights: • AlCr(O{sub x}N{sub 1−x}) layers with variable oxygen content 0 < x < 1 were grown. • The layers with the lowest oxygen content, x < 0.6, electronically behave like nitrides. • Coatings with 0.6 ≤ x < 0.97 are assigned to metastable monoxides. • The oxide region consisted of a solid solution of α-phase with a corundum structure.

Conventional and Synchrotron X-Ray Topography of Defects in the Core Region of SrLaGaO4

International Nuclear Information System (INIS)

Malinowska, A.; Lefeld-Sosnowska, M.; Wieteska, K.; Wierzchowski, W.; Pajaczkowska, A.; Graeff, W.

2008-01-01

SrLaGaO 4 single crystals are perspective substrate materials for high temperature superconductors thin films, elements of thermal radiation receivers and other electronic devices. The defect structure of the Czochralski grown SrLaGaO 4 crystal was investigated by means of X-ray topography exploring both conventional and synchrotron sources. The crystal lattice defects in the core region of the crystal were investigated. The regular network of defects arranged in rows only in direction was observed. Owing to high resolution of synchrotron radiation white beam back reflection topographs one can distinguish individual spots forming the lines of the rows. It can be supposed that these elongated rod-like volume defects are located in f100g lattice planes forming a kind of walls. They are built approximately of the same phase as crystal but crystallize at a different moment than a rest of the crystal due to the constitutional supercooling. (authors)

Investigation of a novel x-ray tube for the calibration of the x-ray crystal spectrometer in the KSTAR machine

International Nuclear Information System (INIS)

Bak, J.G.; Lee, S.G.

2007-01-01

A novel x-ray tube with a line filament has been developed for the in-situ calibration of the x-ray crystal spectrometer (XCS) in the KSTAR machine. The characteristics of the x-ray tube are investigated from the x-ray images obtained by using a pinhole and a CCD detector. It is found that the image has the width of about 0.1 mm, which is much improved as compared with the previous experimental results. In addition, there is a uniform region around the center of the image within its full length of 13.5 mm. This work may lead to the development of a novel x-ray tube with a line focus, which is required for the calibration of the XCS. Experimental results from the investigation of the x-ray tube are presented and the technical issues in a design of the in-situ calibration system using the x-ray tube for the KSTAR XCS are discussed. (author)

Soft x-ray emission from the Lupus Loop and SN 1006 supernova remnants

International Nuclear Information System (INIS)

Winkler, P.F. Jr.; Hearn, D.R.; Richardson, J.A.; Behnken, J.M.

1979-01-01

X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint, extended source of soft x-rays with a temperature about 2.5 x 10 6 K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2--1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star

Note: Application of a pixel-array area detector to simultaneous single crystal x-ray diffraction and x-ray absorption spectroscopy measurements

International Nuclear Information System (INIS)

Sun, Cheng-Jun; Brewe, Dale L.; Heald, Steve M.; Zhang, Bangmin; Chen, Jing-Sheng; Chow, G. M.; Venkatesan, T.

2014-01-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr 0.67 Sr 0.33 MnO 3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam

Transport and magnetic properties of Pr1-x Ca x MnO3 epitaxial films grown on LaAlO3 substrates

International Nuclear Information System (INIS)

Maniwa, A.; Okano, K.; Ohkubo, I.; Kumigashira, H.; Oshima, M.; Lippmaa, M.; Kawasaki, M.; Koinuma, H.

2007-01-01

We have measured physical properties of Pr 1- x Ca x MnO 3 (PCMO) epitaxial thin films with different hole concentrations (x=0.2, 0.3, 0.4, and 0.5) grown on LaAlO 3 (1 0 0) substrates by laser molecular beam epitaxy technique. The temperature dependence of the resistivity shows insulating behavior in all temperature regions and the resistivity itself monotonously decreases as x increases. This insulating nature of PCMO films is similar to that of bulk PCMO crystals. However, we did not find any indication of the resistivity anomaly associated with the onset of charge ordering irrespective of x. These results suggest that the compressive strain strongly suppresses charge-ordered states in PCMO

Handbook of X-Ray Astronomy

Science.gov (United States)

Arnaud, Keith A. (Editor); Smith, Randall K.; Siemiginowska, Aneta

2011-01-01

X-ray astronomy was born in the aftermath of World War II as military rockets were repurposed to lift radiation detectors above the atmosphere for a few minutes at a time. These early flights detected and studied X-ray emission from the Solar corona. The first sources beyond the Solar System were detected during a rocket flight in 1962 by a team headed by Riccardo Giaccom at American Science and Engineering, a company founded by physicists from MIT. The rocket used Geiger counters with a system designed to reduce non-X-ray backgrounds and collimators limiting the region of sky seen by the counters. As the rocket spun, the field of view (FOV) happened to pass over what was later found to be the brightest non-Solar X-ray source; later designated See X-1. It also detected a uniform background glow which could not be resolved into individual sources. A follow-up campaign using X-ray detectors with better spatial resolution and optical telescopes identified See X-1 as an interacting binary with a compact (neutron star) primary. This success led to further suborbital rocket flights by a number of groups. More X-ray binaries were discovered, as well as X-ray emission from supernova remnants, the radio galaxies M87 and Cygnus-A, and the Coma cluster. Detectors were improved and Geiger counters were replaced by proportional counters, which provided information about energy spectra of the sources. A constant challenge was determining precise positions of sources as only collimators were available.

Photoemission measurements for low energy x-ray detector applications

International Nuclear Information System (INIS)

Day, R.H.

1981-01-01

Photoemission has been studied for nearly 100 years as both a means of investigating quantum physics, and as a practical technique for transducing optical/x-ray photons into electrical currents. Numerous x-ray detection schemes, such as streak cameras and x-ray sensitive diodes, exploit this process because of its simplicity, adaptability, and speed. Recent emphasis on diagnostics for low temperature, high density, and short-lived, plasmas for inertial confinement fusion has stimulated interest in x-ray photoemission in the sub-kilovolt regime. In this paper, a review of x-ray photoemission measurements in the 50 eV to 10 keV x-ray region is given and the experimental techniques are reviewed. A semiempirical model of x-ray photoemission is discussed and compared to experimental measurements. Finally, examples of absolutely calibrated instruments are shown

Einstein X-ray survey of the Pleiades - The dependence of X-ray emission on stellar age

Science.gov (United States)

Micela, G.; Sciortino, S.; Serio, S.; Vaiana, G. S.; Bookbinder, J.; Golub, L.; Harnden, F. R., Jr.; Rosner, R.

1985-01-01

The data obtained with two pointed observations of 1 deg by 1 deg fields of the Pleiades region have been analyzed, and the results are presented. The maximum-likelihood X-ray luminosity functions for the Pleiades G and K stars in the cluster are derived, and it is shown that, for the G stars, the Pleiades X-ray luminosity function is significantly brighter than the corresponding function for Hyades G dwarf stars. This finding indicates a dependence of X-ray luminosity on stellar age, which is confirmed by comparison of the same data with median X-ray luminosities of pre-main sequence and local disk population dwarf G stars. It is suggested that the significantly larger number of bright X-ray sources associated with G stars than with K stars, the lack of detection of M stars, and the relatively rapid rotation of the Pleiades K stars can be explained in terms of the onset of internal differential rotation near the convective envelope-radidative core interface after the spin-up phase during evolution to the main sequence.

Direct solution of the biharmonic equation on rectangular regions and the Poisson equation on irregular regions

International Nuclear Information System (INIS)

Buzbee, B.L.; Dorr, F.W.

1974-01-01

The discrete biharmonic equation on a rectangular region and the discrete Poisson equation on an irregular region can be treated as modifications to matrix problems with very special structure. It is shown how to use the direct method of matrix decomposition to formulate an effective numerical algorithm for these problems. For typical applications the operation count is O(N 3 ) for an N x N grid. Numerical comparisons with other techniques are included. (U.S.)

Space- and time-resolved diagnostic of line emission from the separatrix region in JET X-point plasmas

International Nuclear Information System (INIS)

Chabert, P.; Breton, C.; DeMichelis, C.; Mattioli, M.; Ramette, J.; Saoutic, B.; Denne, B.; Giannella, R.; Gottardi, N.; Magyar, G.

1989-01-01

The SPEX GISMO VUV spectrometer installed on JET has appeared to be appropriate to study the impurities radiation during X-point operation. Preliminary results have been obtained with 2 of the 3 spectrometers. They concern mainly the light impurities emission, CIII, O VI in the vicinity of the X-point during the transition from L to H mode. The results are reported for both single X and double X discharges and future prospects are assessed. (author) 4 refs., 6 figs

Development of X-ray microcalorimeter using Ir/Au-TES

International Nuclear Information System (INIS)

Kunieda, Yuichi; Ohno, Masashi; Nakazawa, Masaharu; Takahashi, Hiroyuki; Fukuda, Daiji; Ohkubo, Masataka; Hirayama, Huminori; Ataka, Manabu

2004-01-01

We are developing x-ray mirocalorimeters using transition edge sensors of iridium/gold (Ir/Au-TES) for high resolution x-ray spectroscopy. TES microcalorimeters can achieve faster response than conventional microcalorimeters by keeping the operating point of TES in the transition region through the use of strong negative electrothermal feedback (ETF). At present, the energy resolution of 9.4 eV (FWHM) was achieved for a 5899 eV Mn K al line. At a synchrotron X-ray radiation facility, we demonstrated microscopic signal response profile of the device and high-resolution X-ray fluorescence spectroscopy using a small amount of sample. (author)

Design considerations for an x-ray microprobe

International Nuclear Information System (INIS)

Howells, M.R.; Hastings, J.B.

1982-01-01

The optical design of a fluorescent microprobe covering the x-ray region from 2 to 16 keV is considered for the NSLS x-ray ring. The limit on detectability is from total flux (photons/μm 2 ) and several design choices are considered to match the optical system to the storage ring to maximize throughput. The tradeoffs in image quality and energy resolution of these designs have been considered and within these constraints two firm proposals are presented

QCD expectations for deep inelastic scattering at small x

International Nuclear Information System (INIS)

Kwiecinski, J.

1993-01-01

The basic QCD expectations concerning the deep inelastic scattering at low x where x is the Bjorken scaling variable are reviewed. This includes discussion of the Lipatov equation which sums the leading powers of Ln(1/x) and the shadowing effects. Phenomenological implications of the theoretical expectations for the deep inelastic lepton-hadron scattering in the small x region which will be accessible at the HERA ep collider are described. We give predictions for structure functions F 2 and F L based on the k T factorization theorem and discuss jet production in deep inelastic lepton scattering. The list of other topical problems relevant for the small x physics is given. (author). 46 refs, 7 figs

Characteristics of x-ray radiation from a gas-puff z-pinch plasma

International Nuclear Information System (INIS)

Akiyama, N.; Takasugi, K.

2002-01-01

Characteristics of x-ray radiation from Ar gas-puff z-pinch plasma have been investigated by changing delay time of discharge from gas puffing. Intense cloud structure of x-ray image was observed at small delay time region, but the total x-ray signal was not so intense. The x-ray signal increased with increasing the delay time, and hot spots of x-ray image also became intense. Electron temperature was evaluated from x-ray spectroscopic data, and no significant difference in temperature was observed. (author)

Measurements of atmospheric and gamma rays-balloon experiments at subantartic region

International Nuclear Information System (INIS)

Jayanthi, U.B.; Correa, R.V.; Blanco, F.G.

1986-01-01

The results of two stratospheric balloon experiments conducted to measure the atmospheric X and gamma rays are presented. These experiments, conducted at Comandante Ferraz base in subantarctic region, have provided the spectrum of ground radioactivity in gamma rays (0.2 to 2.9 MeV) and atmospheric X-ray spectra at different altitudes. We specifically chose to discuss the observed ceiling spectrum of X-rays in the 28 to 180KeV region observed at 7.0 g. cm -2 . We have utilized the data of other experiments with different telescope geometries, to evaluate the builup effects due to cosmic ray secondaries in atmosphere. This behaviour, previoulsy studied for atmospheric gamma rays, permitted to compare the up/down flux rations to explain the observed atmospheric X-ray spectrum. (Author) [pt

Semi-inclusive deep inelastic scattering at small-x

International Nuclear Information System (INIS)

Marquet, Cyrille; Xiao, Bo-Wen; Yuan Feng

2009-01-01

We study the semi-inclusive hadron production in deep inelastic scattering at small-x. A transverse-momentum-dependent factorization is found consistent with the results calculated in the small-x approaches, such as the color-dipole framework and the color glass condensate, in the appropriate kinematic region at the lowest order. The transverse-momentum-dependent quark distribution can be studied in this process as a probe for the small-x saturation physics. Especially, the ratio of quark distributions as a function of transverse momentum at different x demonstrates strong dependence on the saturation scale. The Q 2 dependence of the same ratio is also studied by applying the Collins-Soper-Sterman resummation method.

Nonlinear ultrasonic imaging with X wave

Science.gov (United States)

Du, Hongwei; Lu, Wei; Feng, Huanqing

2009-10-01

X wave has a large depth of field and may have important application in ultrasonic imaging to provide high frame rate (HFR). However, the HFR system suffers from lower spatial resolution. In this paper, a study of nonlinear imaging with X wave is presented to improve the resolution. A theoretical description of realizable nonlinear X wave is reported. The nonlinear field is simulated by solving the KZK nonlinear wave equation with a time-domain difference method. The results show that the second harmonic field of X wave has narrower mainlobe and lower sidelobes than the fundamental field. In order to evaluate the imaging effect with X wave, an imaging model involving numerical calculation of the KZK equation, Rayleigh-Sommerfeld integral, band-pass filtering and envelope detection is constructed to obtain 2D fundamental and second harmonic images of scatters in tissue-like medium. The results indicate that if X wave is used, the harmonic image has higher spatial resolution throughout the entire imaging region than the fundamental image, but higher sidelobes occur as compared to conventional focus imaging. A HFR imaging method with higher spatial resolution is thus feasible provided an apodization method is used to suppress sidelobes.

Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jun; Li, Ting; Chen, Huadong, E-mail: zjun@nao.cas.cn, E-mail: hdchen@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2017-08-10

From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections. To examine the structures of the four flares close to the solar disk center from October 22 to 26, we firstly employ composite triple-time images in each flare process to display the stratified structure of these flare loops. The loop structures of each flare in both the lower (171 Å) and higher (131 Å) temperature channels are complex, e.g., the flare loops rooting at flare ribbons are sheared or twisted (enwound) together, and the complex structures were not destroyed during the flares. For the first flare, although the flare loop system appears as a spindle shape, we can estimate its structures from observations, with lengths ranging from 130 to 300 Mm, heights from 65 to 150 Mm, widths at the middle part of the spindle from 40 to 100 Mm, and shear angles from 16° to 90°. Moreover, the flare ribbons display irregular movements, such as the left ribbon fragments of the flare on October 22 sweeping a small region repeatedly, and both ribbons of the flare on October 26 moved along the same direction instead of separating from each other. These irregular movements also imply that the corresponding flare loops are complex, e.g., several sets of flare loops are twisted together. Although previous studies have suggested that the background magnetic fields prevent confined flares from erupting,based on these observations, we suggest that complex flare loop structures may be responsible for these confined flares.

Complex dielectric modulus and relaxation response at low microwave frequency region of dielectric ceramic Ba6-3xNd8+2xTi18O54

Directory of Open Access Journals (Sweden)

Chian Heng Lee

2014-10-01

Full Text Available The desirable characteristics of Ba6-3xNd8+2xTi18O54 include high dielectric constant, low loss tangent, and high quality factor developed a new field for electronic applications. The microwave dielectric properties of Ba6-3xNd8+2xTi18O54, with x = 0.15 ceramics at different sintering temperatures (600–1300°C were investigated. The phenomenon of polarization produced by the applied electric field was studied. The dielectric properties with respect to frequency from 1 MHz to 1.5 GHz were measured using Impedance Analyzer, and the results were compared and analyzed. The highest dielectric permittivity and lowest loss factor were defined among the samples. The complex dielectric modulus was evaluated from the measured parameters of dielectric measurement in the same frequency range, and used to differentiate the contribution of grain and grain boundary.

Structure of liquid Au-Si alloys around the eutectic region

Energy Technology Data Exchange (ETDEWEB)

Takeda, S. [Faculty of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan)], E-Mail: takeda@rc.kyushu-u.ac.jp; Fujii, H. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kawakita, Y. [Faculty of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kato, Y. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Fujita, S. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Yokota, Y. [Graduate School of Sciences, Kyushu University, Ropponmatsu Fukuoka 810-8560 (Japan); Kohara, S. [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouo Mikazuki-cho, Sayou-gun Hyogo 670-5198 (Japan)

2007-03-25

X-ray diffraction measurements have been carried out for liquid Au-Si alloys around the eutectic region by the transmission method using high-energy X-ray to investigate the atomic arrangements in the liquid state. From the temperature dependence of the observed structure factors, the partial pair correlation and the detailed atomic arrangements will be discussed on the basis of a Reverse Monte Carlo analysis. The reproduced atomic arrangements around the eutectic region suggest the substitution structure and also rather dense liquid with decreasing temperature.

Influence of CdCl{sub 2} activation treatment on ultra-thin Cd{sub 1−x}Zn{sub x}S/CdTe solar cells

Energy Technology Data Exchange (ETDEWEB)

Clayton, A.J., E-mail: a.clayton@glyndwr.ac.uk [Centre for Solar Energy Research, Glyndŵr University, OpTIC, St. Asaph LL17 0JD (United Kingdom); Baker, M.A.; Babar, S. [Faculty of Engineering & Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); Gibson, P.N. [Institute for Health & Consumer Protection, Joint Research Centre, 21020 Ispra, VA (Italy); Irvine, S.J.C.; Kartopu, G.; Lamb, D.A.; Barrioz, V. [Centre for Solar Energy Research, Glyndŵr University, OpTIC, St. Asaph LL17 0JD (United Kingdom)

2015-09-01

Ultra-thin CdTe photovoltaic solar cells with an absorber thickness of 0.5 μm were produced by metal organic chemical vapour deposition onto indium tin oxide coated boroaluminosilicate glass. A wide band gap Cd{sub 1−x}Zn{sub x}S alloy window layer was employed to improve spectral response in the blue region of the solar spectrum. X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy were used to monitor changes in the chemical composition and microstructure of the Cd{sub 1−x}Zn{sub x}S/CdTe solar cell after varying the post-deposition CdCl{sub 2} activation treatment time and annealing temperature. The CdCl{sub 2} treatment leached Zn from the Cd{sub 1−x}Zn{sub x}S layer causing a redshift in the spectral response onset of window absorption. S diffusion occurred across the Cd{sub 1−x}Zn{sub x}S/CdTe interface, which was more pronounced as the CdCl{sub 2} treatment was increased. A CdTe{sub 1−y}S{sub y} alloy was formed at the interface, which thickened with CdCl{sub 2} treatment time. Small concentrations of S (up to 2 at.%) were observed throughout the CdTe layer as the degree of CdCl{sub 2} treatment was increased. Greater S diffusion across the Cd{sub 1−x}Zn{sub x}S/CdTe interface caused the device open-circuit voltage (V{sub oc}) to increase. The higher V{sub oc} is attributed to enhanced strain relaxation and associated reduction of defects in the interface region as well as the increase in CdTe grain size. - Highlights: • Increased CdCl{sub 2} activation treatment resulted in loss of Zn from Cd{sub 1−x}Zn{sub x}S. • Sulphur diffusion into CdTe was enhanced with greater CdCl{sub 2} activation treatment. • Improvement to V{sub oc} correlated with increased sulphur diffusion into CdTe.

Multiple scattering approach to X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Benfatto, M.; Wu Ziyu

2003-01-01

In this paper authors present the state of the art of the theoretical background needed for analyzing X-ray absorption spectra in the whole energy range. The multiple-scattering (MS) theory is presented in detail with some applications on real systems. Authors also describe recent progress in performing geometrical fitting of the XANES (X-ray absorption near-edge structure) energy region and beyond using a full multiple-scattering approach

Relationship between electrical and structural properties in Pr2/3+xTiO3±y

International Nuclear Information System (INIS)

Kirsanov, N.A.; Bazuev, G.V.

1987-01-01

Synthesis conditions results of X-ray diffraction investigations and electric properties of oxide titanium bronzes (OTB) of praseodymium Pr 2/3+x TiO 3±y in homogeneity region are presented. Change of crystal lattice symmetry in the region of existence of oxide titanium bronzes Pr 2/3+x TiO 3 ± y (O ≤ x ≤ 1/3) was revealed. Specific electrical resistance measurements enabled to conclude that d-electrons of Ti 3+ cations were characterized by collectivized behaviour, conditioned by formation of harrow, partially occupied π*-zone

Development of Compact Soft X-ray Source Based on Laser Undulator

CERN Document Server

Kuroda, Ryunosuke; Minamiguchi, S; Saitô, T; Ueyama, D; Washio, Masakazu

2004-01-01

A compact soft X-ray source is required in various research fields such as material and biological science. The laser undulator based on backward Compton scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. It is performed in a water window region (250eV - 500 eV) using the interaction between 1047 nm Nd:YLF laser and 4 MeV high quality electron beam generated from rf gun system. The range of energy in the water window region has K-shell absorption edges of Oxygen, Carbon and Nitrogen, which mainly constitute of living body. Since the absorption coefficient of water is much smaller than the protein’s coefficient in this range, a dehydration of the specimens is not necessary. As a preliminary experiment, about 300 eV X-ray generation was carried out. As next step, soft X-ray optics with zone plate was proposed for Soft X-ray microscopy. In this conference, we will report details and results of the experiment.

The proton structure function F sub 2 sup p (x, Q sup 2) at small x in the framework of extended Regge-Eikonal approach

CERN Document Server

Petrov, V A

2001-01-01

The behaviour of the proton structure function F sub 2 sup p (x, Q sup 2) in the region of small x is described in the framework of the generalized off-shell extention of the Regge-eikonal approach which automatically takes into account off-shell unitarity. A good quality is achieved of description of the experimental data for x < 10 sup - sup 2 and it is argued that the data on F sub 2 sup p (x, Q sup 2) measured at HERA can be fairly well described with classical universal Regge trajectories. No extra, hard trajectories of high intercept are needed for that. The x, Q sup 2 slopes and the effective intercept are discussed as functions of x and Q sup 2

The hypersoft state of Cygnus X-3. A key to jet quenching in X-ray binaries?

Science.gov (United States)

Koljonen, K. I. I.; Maccarone, T.; McCollough, M. L.; Gurwell, M.; Trushkin, S. A.; Pooley, G. G.; Piano, G.; Tavani, M.

2018-04-01

Context. Cygnus X-3 is a unique microquasar in the Galaxy hosting a Wolf-Rayet companion orbiting a compact object that most likely is a low-mass black hole. The unique source properties are likely due to the interaction of the compact object with the heavy stellar wind of the companion. Aim. In this paper, we concentrate on a very specific period of time prior to the massive outbursts observed from the source. During this period, Cygnus X-3 is in a so-called hypersoft state, in which the radio and hard X-ray fluxes are found to be at their lowest values (or non-detected), the soft X-ray flux is at its highest values, and sporadic γ-ray emission is observed. We use multiwavelength observations to study the nature of the hypersoft state. Methods: We observed Cygnus X-3 during the hypersoft state with Swift and NuSTAR in X-rays and SMA, AMI-LA, and RATAN-600 in the radio. We also considered X-ray monitoring data from MAXI and γ-ray monitoring data from AGILE and Fermi. Results: We found that the spectra and timing properties of the multiwavelength observations can be explained by a scenario in which the jet production is turned off or highly diminished in the hypersoft state and the missing jet pressure allows the wind to refill the region close to the black hole. The results provide proof of actual jet quenching in soft states of X-ray binaries.

Time resolved x-ray photography of a dense plasma focus

International Nuclear Information System (INIS)

Burnett, J.C.; Meyer, J.; Rankin, G.

1977-01-01

The temporal development of the hot plasma in a dense plasma focus is studied by x-ray streak photography of approximately 2 ns resolution time. It is shown that initially a uniform x-ray emitting pinch plasma is formed which subsequently cools down until x-ray emission stops after approximately 50 ns. At a time of around 100 ns after initial x-ray emission coinciding with the break-up time of the pinch a second burst of x-rays is observed coming from small localized regions. The observations are compared with results obtained from time-resolved shadow and schlieren photography of a similar dense focus discharge. (author)

Juno/JEDI observations of 0.01 to >10 MeV energetic ions in the Jovian auroral regions: Anticipating a source for polar X-ray emission

Science.gov (United States)

Haggerty, D. K.; Mauk, B. H.; Paranicas, C. P.; Clark, G.; Kollmann, P.; Rymer, A. M.; Bolton, S. J.; Connerney, J. E. P.; Levin, S. M.

2017-07-01

After a successful orbit insertion, the Juno spacecraft completed its first 53.5 day orbit and entered a very low altitude perijove with the full scientific payload operational for the first time on 27 August 2016. The Jupiter Energetic particle Detector Instrument measured ions and electrons over the auroral regions and through closest approach, with ions measured from 0.01 to >10 MeV, depending on species. This report focuses on the composition of the energetic ions observed during the first perijove of the Juno mission. Of particular interest are the ions that precipitate from the magnetosphere onto the polar atmosphere and ions that are accelerated locally by Jupiter's powerful auroral processes. We report preliminary findings on the spatial variations, species, including energy and pitch angle distributions throughout the prime science region during the first orbit of the Juno mission. The prime motivation for this work was to examine the heavy ions that are thought to be responsible for the observed polar X-rays. Jupiter Energetic particle Detector Instrument (JEDI) did observe precipitating heavy ions with energies >10 MeV, but for this perijove the intensities were far below those needed to account for previously observed polar X-ray emissions. During this survey we also found an unusual signal of ions between oxygen and sulfur. We include here a report on what appears to be a transitory observation of magnesium, or possibly sodium, at MeV energies through closest approach.

X-ray scanning of overhead aurorae from rockets

International Nuclear Information System (INIS)

Barcus, J.R.; Goldberg, R.A.

1981-01-01

Two Nike Tomahawk rocket payloads were launched into energetic auroral events to investigate their structure and effects on the atmosphere. The instrument complement included X-ray scintillation detectors with energy discrimination in four ranges to measure the deposition of bremsstrahlung produced X-rays within the stratosphere and mesosphere. For this purpose, each instrument was designed for wide angle viewing; however, properties of the rocket motion have permitted coarse observation of distinct spatial X-ray structure. The detectors were mounted at a 45 0 angle with respect to the payload axis to permit scanning of the upper hemisphere, with rocket spin rates near 5 c/s during the upleg portion of each flight. Here, atmospheric shielding reduced energetic particle contamination effects to insignificant values below 65 to 75 km. Iterative computer techniques were used to reconstruct X-ray source maps at 100 km, taking atmospheric absorption effects into account. Payload 18.178 was launched on 21 September (0302 LMT) into an aurora observed to have two distinct azimuthal regions of optical brightness. Payload 18.179 (23 September, 0147 LMT) was launched into an aurora of more diffuse character. The presence of a two component spectrum is indicated for each event with the hard component originating in the more diffuse, optically faint regions. (author)

Solar active region display system

Science.gov (United States)

Golightly, M.; Raben, V.; Weyland, M.

2003-04-01

The Solar Active Region Display System (SARDS) is a client-server application that automatically collects a wide range of solar data and displays it in a format easy for users to assimilate and interpret. Users can rapidly identify active regions of interest or concern from color-coded indicators that visually summarize each region's size, magnetic configuration, recent growth history, and recent flare and CME production. The active region information can be overlaid onto solar maps, multiple solar images, and solar difference images in orthographic, Mercator or cylindrical equidistant projections. Near real-time graphs display the GOES soft and hard x-ray flux, flare events, and daily F10.7 value as a function of time; color-coded indicators show current trends in soft x-ray flux, flare temperature, daily F10.7 flux, and x-ray flare occurrence. Through a separate window up to 4 real-time or static graphs can simultaneously display values of KP, AP, daily F10.7 flux, GOES soft and hard x-ray flux, GOES >10 and >100 MeV proton flux, and Thule neutron monitor count rate. Climatologic displays use color-valued cells to show F10.7 and AP values as a function of Carrington/Bartel's rotation sequences - this format allows users to detect recurrent patterns in solar and geomagnetic activity as well as variations in activity levels over multiple solar cycles. Users can customize many of the display and graph features; all displays can be printed or copied to the system's clipboard for "pasting" into other applications. The system obtains and stores space weather data and images from sources such as the NOAA Space Environment Center, NOAA National Geophysical Data Center, the joint ESA/NASA SOHO spacecraft, and the Kitt Peak National Solar Observatory, and can be extended to include other data series and image sources. Data and images retrieved from the system's database are converted to XML and transported from a central server using HTTP and SOAP protocols, allowing

Intensity interferometry at the X13A undulator beamline

International Nuclear Information System (INIS)

Gluskin, E.; McNulty, I.; Yang, L.; Randall, K.J.; Johnson, E.D.

1993-01-01

We are constructing a soft x-ray intensity interferometer and an undulator based beamline to demonstrate intensity interferometry in the x-ray region. The 10-period soft x-ray undulator at the NSLS provides the necessary coherent flux; the X13A beamline is designed to preserve the spatial coherence of the bright x-ray beam and provide sufficient temporal coherence using a horizontally deflecting spherical grating monochromator. Using the interferometer, which consists of an array of small slits, a wedge-shaped beamsplitter and two fast microchannel plate detectors, we expect to measure the spatial coherence of the undulator beam and therefore the size of the source in the vertical plane. Details of the bean-dine design and the interferometer experiment are discussed

Loss of heterozygosity on the X chromosome in human breast cancer.

Science.gov (United States)

Loupart, M L; Adams, S; Armour, J A; Walker, R; Brammar, W; Varley, J

1995-08-01

The analysis of loss of heterozygosity (LOH) in tumours can be a powerful tool for mapping the sites of tumour suppressor genes in the human genome. A panel of breast cancer patients was assembled as pairs of tumour and lymphocyte DNA samples and LOH studies carried out by Southern hybridisation with polymorphic loci mapping to the X chromosome with appropriate controls. Deletion mapping revealed a high frequency of small regionalised deletions, defining at least three independent regions, one of which is particularly well mapped to a 500 kb stretch of DNA in the distal portion of the pseudoautosomal region of Xp. A second region has been identified within the pseudoautosomal region close to the pseudoautosomal boundary, and there is a third discrete site of loss on distal Xq. Perturbations of sequences at these regions represent independent events in a number of patients. This study represents the first detailed analysis of LOH on the X chromosome in human breast tumours, the results of which indicate that at least three regions of this chromosome are involved in the disease.

ON MULTIPLE RECONNECTION X-LINES AND TRIPOLAR PERTURBATIONS OF STRONG GUIDE MAGNETIC FIELDS

International Nuclear Information System (INIS)

Eriksson, S.; Gosling, J. T.; Lapenta, G.; Newman, D. L.; Goldman, M. V.; Phan, T. D.; Lavraud, B.; Khotyaintsev, Yu. V.; Carr, C. M.; Markidis, S.

2015-01-01

We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar wind reconnection exhaust in the presence of a guide field B M   which is almost four times as strong as the reversing field B L . The novel tripolar field consists of two narrow regions of depressed B M , with an observed 7%–14% ΔB M magnitude relative to the external field, which are found adjacent to a wide region of enhanced B M within the exhaust. A stronger reversing field is associated with each B M depression. A kinetic reconnection simulation for realistic solar wind conditions and the observed strong guide field reveals that tripolar magnetic fields preferentially form across current sheets in the presence of multiple X-lines as magnetic islands approach one another and merge into fewer and larger islands. The simulated ΔB M /ΔX N over the normal width ΔX N between a B M minimum and the edge of the external region agree with the normalized values observed by Cluster. We propose that a tripolar guide field perturbation may be used to identify candidate regions containing multiple X-lines and interacting magnetic islands at individual solar wind current sheets with a strong guide field

SU-F-I-12: Region-Specific Dictionary Learning for Low-Dose X-Ray CT Reconstruction

International Nuclear Information System (INIS)

Xu, Q; Han, H; Xing, L

2016-01-01

Purpose: Dictionary learning based method has attracted more and more attentions in low-dose CT due to the superior performance on suppressing noise and preserving structural details. Considering the structures and noise vary from region to region in one imaging object, we propose a region-specific dictionary learning method to improve the low-dose CT reconstruction. Methods: A set of normal-dose images was used for dictionary learning. Segmentations were performed on these images, so that the training patch sets corresponding to different regions can be extracted out. After that, region-specific dictionaries were learned from these training sets. For the low-dose CT reconstruction, a conventional reconstruction, such as filtered back-projection (FBP), was performed firstly, and then segmentation was followed to segment the image into different regions. Sparsity constraints of each region based on its dictionary were used as regularization terms. The regularization parameters were selected adaptively according to different regions. A low-dose human thorax dataset was used to evaluate the proposed method. The single dictionary based method was performed for comparison. Results: Since the lung region is very different from the other part of thorax, two dictionaries corresponding to lung region and the rest part of thorax respectively were learned to better express the structural details and avoid artifacts. With only one dictionary some artifact appeared in the body region caused by the spot atoms corresponding to the structures in the lung region. And also some structure in the lung regions cannot be recovered well by only one dictionary. The quantitative indices of the result by the proposed method were also improved a little compared to the single dictionary based method. Conclusion: Region-specific dictionary can make the dictionary more adaptive to different region characteristics, which is much desirable for enhancing the performance of dictionary learning

SU-F-I-12: Region-Specific Dictionary Learning for Low-Dose X-Ray CT Reconstruction

Energy Technology Data Exchange (ETDEWEB)

Xu, Q; Han, H; Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

2016-06-15

Purpose: Dictionary learning based method has attracted more and more attentions in low-dose CT due to the superior performance on suppressing noise and preserving structural details. Considering the structures and noise vary from region to region in one imaging object, we propose a region-specific dictionary learning method to improve the low-dose CT reconstruction. Methods: A set of normal-dose images was used for dictionary learning. Segmentations were performed on these images, so that the training patch sets corresponding to different regions can be extracted out. After that, region-specific dictionaries were learned from these training sets. For the low-dose CT reconstruction, a conventional reconstruction, such as filtered back-projection (FBP), was performed firstly, and then segmentation was followed to segment the image into different regions. Sparsity constraints of each region based on its dictionary were used as regularization terms. The regularization parameters were selected adaptively according to different regions. A low-dose human thorax dataset was used to evaluate the proposed method. The single dictionary based method was performed for comparison. Results: Since the lung region is very different from the other part of thorax, two dictionaries corresponding to lung region and the rest part of thorax respectively were learned to better express the structural details and avoid artifacts. With only one dictionary some artifact appeared in the body region caused by the spot atoms corresponding to the structures in the lung region. And also some structure in the lung regions cannot be recovered well by only one dictionary. The quantitative indices of the result by the proposed method were also improved a little compared to the single dictionary based method. Conclusion: Region-specific dictionary can make the dictionary more adaptive to different region characteristics, which is much desirable for enhancing the performance of dictionary learning

Design and fabrication of micro X-ray diffraction system

International Nuclear Information System (INIS)

Park, Yang Soon; Han, Sun Ho; Kim, Jong Goo; Jee, Kwang Yong

2006-10-01

It has been observed that microstructure changes occur at the pellet periphery(rim) of the fuel at very high burn-up. Despite its narrow range (below some hundreds microns in depth), this peripheral region(rim) determines the behaviour of nuclear fuel. To determine lattice parameter with XRD at intervals as small as 30-50 μ m in radial direction of irradiated fuel samples, a micro X-ray diffraction system was designed and fabricated. This report describes the micro X-ray diffraction system consisted of an X-ray microbeam alignment system and a sample micro translation system, its characterization, and its performance test through the analysis for the micro region of some specimens. This system will be set in a radiation shielded glove box, and then used for analysis of lattice parameter change and the phase change at intervals as small as 30-50 μ m in radial direction of the rim of an irradiated fuel sample and a fuel cladding

Design and fabrication of micro X-ray diffraction system

Energy Technology Data Exchange (ETDEWEB)

Park, Yang Soon; Han, Sun Ho; Kim, Jong Goo; Jee, Kwang Yong

2006-10-15

It has been observed that microstructure changes occur at the pellet periphery(rim) of the fuel at very high burn-up. Despite its narrow range (below some hundreds microns in depth), this peripheral region(rim) determines the behaviour of nuclear fuel. To determine lattice parameter with XRD at intervals as small as 30-50 {mu} m in radial direction of irradiated fuel samples, a micro X-ray diffraction system was designed and fabricated. This report describes the micro X-ray diffraction system consisted of an X-ray microbeam alignment system and a sample micro translation system, its characterization, and its performance test through the analysis for the micro region of some specimens. This system will be set in a radiation shielded glove box, and then used for analysis of lattice parameter change and the phase change at intervals as small as 30-50 {mu} m in radial direction of the rim of an irradiated fuel sample and a fuel cladding.

Influence of concentration and temperature on tunneling and rotational dynamics of ammonium in Rb1-x (NH4)x I mixed crystals

International Nuclear Information System (INIS)